Yes, Ive been down the power crazed '55 route. Replaced the standard leather washer unit with a modern plastic parachute seal, bigger spring etc. I turned a lovely accurate shooting gun into a 10.5ft.lbs monster. I soon reverted it back to original.
Personally I find the Walther Mod 55s to be better shooters. Easier to cock and very smooth/little recoil.

HTH
Ian