What is the "best" cartridge a Technics 1210...

So, my upgrade plan is:
1. cartridge
2. tonearm wires
3. headshell wires
4. achromat mat
5. isonoe feets

And I guess this is the moment where there won't be anything more that I would ask from my 1210 :)

I was considering Denon DL-301 MK2 after reading a lot of good reviews. My question is, what about the headshell. I would like to update the stock headshell, buton technics tonearm it has 12g effective tonearm mass. And all the good headshells I see are 12g, so a little math:
(12-7.5+12) = 16.5g - effective tonearm mass with the new headshell.
where:
-7.5 stock technics headshell
12 - new headshell

And this will move the resonanse to a point, where it's not good, right?

Do you guys have any suggestion for a good headshell, that will sound better than the stock one?

And one more question. I can hear the power supply when I turn maximum gain on anything. I know it's the power supply because when I turn off the turntable this low noise stops.. 
Will the achromat mat help to reduce it? Or maybe better feet?
I still don't want to touch the original technics power supply.

I tried AT150mlx but it was too bright for me, on Ifi phono 2 with 100pf load. I changed the external wires with very good ones, so probably it's because I need to rewire the tonearm.

http://www.needledoctor.com/Denon-DL-103R-Cartridge
It looks like this cartrige makes perfect match with Technics stock tonearm, when used with 12gr headshells which are easier to find :)
Maybe I should rethink my choise, but from what I read 301 is more warm, which is something I really like... But actually I'm not sure because it is so subjective, does anyone listen to both cartriges (103R and 301 MK2) to tell what are there strengths and weaknesses.

@chakster  Hi, there, thanks for the perfect reply.
I made the calculations, and actually it turned out that for the resonant point of view, the headshell should be even less than 6g, in order to match the perfect 10Hz resonant frequency.
But I also read that MC cartriges need higher mass headshells, for some reason.
Maybe the original technics headshell is perfect after all, but I will have to change its wires, because they are very basic. Also, I'm not sure about it's material, from another forum I read MC should Not be used with headshells that have anything metal on them. 

About Discovery Tonearm Wire .. Is this the best choice for technics stock arm? Or at least is it good enough for me, after all I'm not gonna use it with $1k+ cartriges after all. But it seem cheap, for such an important thing as the wires for the tonearm.

Btw, one stupid question.. does the feet upgrade helps, if I listen only with headphones? the same question for the mat.

SAEC SS-300 looks expensive, and I read a lot of reviews for achromat mat for 1210.. it looks like it's better than the stock rubber mat. So I'll try it. But still the main question is what cartridge.. I really liked to try MC cartridge, and I guess it will happen that I will try both 301 and 103 and decide for my taste..

Thanks again.
Yes, DL-103R with a proper headshell becomes too heavy, for the stock tonearm, I did the calculations.. 
From what I read the best match as MM is probably Nagaoka MP500, but I really want to try MC to hear what is it all about. So I'll take a risk with 301 MK2. The only problem is I don't see a good headshell around 6g for it in ebay :)

Btw, do you know what is the material in technics stock headshell, maybe it's not that bad after all, and I don't need to change it. Just new lead wires will be fine.

And I decided this rewire kit for the tonearm:
http://www.ebay.co.uk/itm/171140634010

The problem is that on the picture I see only external cable.. but it says for the tonearm.. so there should be the internal cables too I guess..

@chakster  what do you think about this rewire kit that I gave link on the posts above?

Well, it looks like anything is bad match for the stock tonearm.. but I need to put some cartridge there :)
I still don't want fluid damper, I think the engineers from Panasonic knew what they were doing. The only problem is the wires, and I will change them.
Btw, I really would like to make upgrades step by step, so I can test very well what is the effect after each change, by analyzing the sound + the WAVs downloaded on my computer.

P.S. The bearings actually is one of the very best parts on the 1210, this thing is rough, and proven in time and abuse by so many djs.. I have the feeling that if something is working, don't touch it. Noone knows the long term effect on the new fancy bearing on the motor of the 1210 which is what makes this turntable unique, and its stable speed. Probably it will have some effect on a 1$k+ cartridge, but for the ones I'm looking for, I doubt it.

P.S.#2 Why do you think DL-301 is not a good match, actually I did the math, it looks very good match technically.

@chakster can you send me a link to the best cable only for the tonearm, that you think will match best my needs, so I can order it from ebay.

@sbank which  Dynavector model do you suggest for the stock tonearm, without fluid dampening? (only rewire)

I understand.. Thanks for the advice.
For now I will just try to find the perfect match for the stock tonearm rewired.

For the shipping from Canada.. It will take a long time and probably be very expensive.

http://www.ebay.co.uk/itm/Discovery-Wire-12-Tonearm-Rewire-Kit-Ready-Fitted-Cartridge-Tags-Cardas-So...

Isn't this the same wires?

Thanks, I will order it from ebay, it will be easier for me, and it will arrive much faster.

@chakster  Hi, I still wonder if  isonoe feet will do things better, if I listen only on headphones, i.e. there are no vibrations caused from outside sources. Or the feet kinda damp the vibrations from the motor and transformator as well?

@chakster well, my cables arrived :) but I watched some videos, it looks really complicated to change the tonearm wiring...

I think I don't understand.. what is the motherboard?

Another problem I have is I can't really align it in Baerwald protractor on the technics stock headshell, because even the cartridge is in the most front position, the end point of the protractor is forward 1mm from the tip of the stylus. But it doesn't seem to be bad for the sound, the sound is perfect.
My settings:
Height: 0mm
Weight: 1.4g
Antiskating: 2

I don't know if it's optimal, but on the stock technics.. this seems to work.

Today changed it a bit.. Weight: 1.5g, Antiscate: 2.5
For some reason it is better, than the recommended 1.4

@chakster I need advice on the headshell, can you recommend me some nice one, with mass less or equal to the mass of the stock technics headshell. 
And another question - I need to buy some good headshell wires. Can you recommend me something good for Denon DL-301mk2

I had problems with antiscating less than this on Hi Fi News testing record. The tracking tests were not good.

you can send me a link to check that Jelco headshells, although I prefer something from Japan :)

ZYX LIVE-18B looks impressive. How much it weights?

Btw my upgrade plan - I changed the mat, the cartridge, I have the discovery wiring, need to set it. I ordered oyaide silver headshell wiring.
The only thing left is the headshell and the isonoe feet. :)

And I think I'm ready :)

@chakster I replaced the wiring, and I must say the sounds is really impressive. I have a question though, now I'm in doubt. Do you unsplit the cables when you put them in the tonearm. Because I put them as they came (i.e. splitted, like in the picture).

I hope it will loosen.. with time. I'm not sure if there is tension now, but the Audio Hi Fi News testing record tracks fine, the first 3 tracks.
Only the torture track is not tracked well.. So I guess I'm fine.

And one more question.. With Denon DL301 MK2 I have highs, but.. they are kinda not so in your face. All my other needles, mostly AT, gave me very strong high frequencies.. With Denon.. they are kinda off, although I put 1KOhm on the preamp. Wondering.. maybe it still breaks in, it's not more than 10 hours running time, so I guess I'll have to wait.

But.. I'm not saying they are missing, they are just not so everywhere in the air, but kinda backward on the stage.
Does anyone else experience this while running in this cartridge?

Actually, after many listening tests, I discovered that the Achromat Mat is reducing the treble... very strange.
I made both recording with stock mat, and with the achromat mat, and seems like the problem is coming from the mat.
I gave the rips to several friends, they all like better the stock mat recording.
Is this normal?

:) 
Well, actually after I replaced the headshell with Audio Technica MG-10 and Oyade Heashell leads, the sound is really amazing.
Now one thing bothers me.. it's the stock PSU. Isn't it enough just to move the transformer outside?

@chakster Well, I don't think there is anything wrong with the stock PSU or the stock tonearm.

 The problem is MC cartridges are too sensitive, and when it goes to the inner part of the vinyl, it gets some of the electromagnetic field. So I wonder, why not just to move it outside, or try to put something that reduces the field, between the transformer and the cartridge?

I'm not saying I don't hear the transformator with MM carts either :)
It's easy, Put the needle on the record, in the last grooves. And don't play it just switch the power know ON/OFF. When it's on, you will hear it, on maximum volume of the speakers.

@chakster do the isonoe feets make any difference? I have serious doubts about these.