Is the Rega P25 and ZYX Fuji really compatible?

I'm looking to step up my analogue listening experience and am thinking of moving from a Dynavector 10x4 MKII to the ZYX R-100 Fuji FS. Would this be a good investment considering my table - tonearm combination consists of REGA's Planar 25 and RB600 slightly modified with Express Machining's Heavyweight and VTA? I'm also considering bypassing my Musical Fidelity A3cr Phono out and using a descrete Phono Stage i.e. Acoustech's PH-1P or Camelot's Lancelot Pro.
They are compatible, but not logical. It rarely makes sense to spend more on the cartridge than on the TT. You can always get more sonic benefits by upgrading the TT, than by spending so much on a cartridge.
Thanks for your feedback. Would you also follow that same line of reasoning regarding upgrading to a descrete phono stage?
I absolutely disagree with twl that you can always get more sonic benefits form upgrading the turntable. From real music listening experience, it is clear that tt differences are subtle (important, I agree, but subtle) compared to the wide range of sonic signature (including arm/cartridge/table mismatches) differences you get from changing cartidges.
Your TT is the weak link. Sorry, but the Rega's are way overrated...