That would be something to ask Mark at Powerhouse as he has extensive knowlege of the GRP engines. I have a mill from both of the mentioned modders and cant say anything bad about either. Powerhouse may be alittle easier to get ahold of though, but I could be wrong. 9 times out 0f 10 your gonna want to get a PSR set and have it modded and the other day at the track i was talking to mark and he was talking about your exact dilemma, with some of the deals out there right now you are probably better off just getting a new mill and getting it done up. Online shops with the cupons and what not ect.