the 2.2 litre motor..the 5sfe is a motor designed for the later generations of run around shitcan celicas, the motor makes fuck all power and is designed for economy not performance...that will be a down grade majorly..as it pulled a much lighter car than the 165 around alot SLOWER...the later gtfours were still 2.O litre, they just had later generations of the 3sgte in them, as far as my 165 goes i am running 12 psi on stock internals, and i have done sfa apart from a pod filter ect, and i am more than happy with the results. at one stage i wanted to keep it all origional genuine parts...but then when i started getting prices for parts from toyota...i decided that wasnt going to be the case at all... near $8OO for a radiator fan motor alone, if u really want to get alot more go out of it, try and get the 3rd or 4th generation of 3sgte and cram that in there...in a couple of years i hope to get my hands on a 4th generation 3sgte and squeeze it in..cheers