Specific to CROFT phono users

I would never sacrifice detail and openness for warmth. I think the very nature of high fidelity demands we extract as much detail as possible. If the system is balanced and tuned, the warmth should be present by default. Harshness and distortion can present as brightness and false detail.

Agree with your point that nothing in the chain can make that back. I am  willing to sacrifice some detail. I have the Harbeth P3's are in a smaller square shape room, around 11 X11 feet... I'm willing to sacrifice some openness and detail for warmth. I think if the right balance is found, the Harbeth's will hold up their end of the bargain. A matter of opinion, but I feel that feeding this system with a cartridge and/or tubes with plenty of body is playing to the strengths of the P3's. 

@fjn I should also note that your preference for warm (i.e. colored) sound indicated by preferring the JJs may mean you will be happy with less ultimate detail. I’m not sure. I know that when I changed my JJs out for Telefunkens, it was like I’d cleaned my windshield.

I have read good things about the Audionote/Goldring IQ3. For me, it's all about speed and detail and that is where the London(Decca)/Croft shines. Nothing you do in the chain afterwards can make that back. I've avoided adding another stage of gain. I have spoken to Glenn Croft on a number of occasions on the MM/MC debacle and his advice was to stay with the Decca. I run two rigs with 2 Crofts and have not been tempted to move to LOMC such is the awesomeness of the music it produces.

noromance- You're 100% correct...I have indeed been on the fence on this. I have been afforded the luxury of listening to the Charisma 103 with my Homage Step Up, but the hope is to no longer need to do that. With regard the the Tubes, I bought the Amperex Holland (match pr branded Hammond) for phono, and single branded miniwatt for amp section. They throw a wide open soundstage, and have less grain than the stock JJ's. But dare I say the JJ's are warmer, which is an aspect I may not want to give up. I have another week on my trial period to decide on that. I eliminated the London, only because of it's idiosyncrasies, which of course is not a big deal to some. Admittedly, I've been up/down on buying an SUT, or giving the Charisma some time off in favor of a HO/MM. Now leaning toward the latter... the Hana Shibata H, with Audio Note IQ 3 also in the mix. My reason for the new thread...I'm simply wondering if If a good MM, and Croft, is just about as good as I can do.
In other words, maybe I'm giving the phono integrated a bit too much credit, and not considering there is a CEILING of performance that a good MM will reach w/o going MC crazy. 

MM. Or a London Decca SG.
IIRC, this is your second system and you’ve been on the fence a while on this. For the standard Croft Integrated, I’d stick with the following:
1. Your upgraded BB tubes if you are happy with them. 
2. A new power cable.
3. Remove the lid if possible (sounds more "open")
4. A MM as many have suggested.

If you want to get into MC, then you might want separates like the Micro 25R phono and perhaps solder in a SUT.