What tonearm will better mine?


I have been running a 12" Jelco SA750L with an upgraded Decca Super Gold on a Garrard 401 for a few years. I'm happy with the sound and happy with my pre, power and speakers. (Croft 25R, EICO HF35s, -good tubes, Quad 57).
I keep hearing that my tonearm is a weak link even though it sounds pretty awesome to me. What would it take to replace the Jelco and make a significant improvement? What should I expect to hear better? Would I have to drill the massive plinth? Thanks.
128x128noromance
Why not first get a very good tonearm cable? the internal wire is decent stuff (silver I think) but a nordost tonearm cable will be a big jump forward, as would a furutech for instance
Which of the arms mentioned have on-the-fly or at least easily repeatable VTA? I am surprised to see many tonearms that are raved about don't have easily repeatable VTA and I wonder if their owners don't adjust VTA for each LP or what? I know Pete Riggle sells adapters for Regas and a few others, but do you guys not adjust VTA with some of these arms? Thanks.
Cheers,
Spencer
Hi Noromance

You should try a "WOODY" From Pete Riggle. I have had a system very similar to yours and my 401/Woody/SPU  really made music in that combination.
A tone arm can be a weak link.   Your's is not!   The Decca is an excellent, but very finicky cartridge!   If its working well?  That means your arm has to be excellent.  Leave it alone.   I have destroyed Deccas not using a tonearm that will work with a Decca. 

Deccas I love.   They eliminate the obscuring of the signal that using rubber for the regular cantilever's bushing. The tonearm has to be exceptional to work well with a Decca. If you are looking for a way to improve  it may be a different tonearm cable.  But, if the Decca works fine?  It means the arm is excellent! 

 I used Mayware V with my Decca super gold and was very pleased

Then I have changed to Graham 2 supreme and could not believe how much better it is in every parameter. As I understand decca work best with unipivots.By the way TT is Nottingham Spacedeck