I, too, have the same Rega P5 setup with the TTPSU. Mt dealerer AND the USA distributor was very adamant about not 'tweaking' the Rega sound. Also, if you rewire it will void your warranty. I am quite happy with my stock sound.
Rega upgrades/tweeks
I am soon to be the owner of a new P5, Exact II and seperate power supply. I know all about "not messing with the Rega sound." However, I AM curious re others experiences. Esp the Expresimo Heavy Weight and end sub, thanks.