The ecu is a nightmare of a job to get a plug and play tem such as power fc..... anything else piggy back, no problems... I have put a power fc in my stagea ( with alot of messing around )and it is good. Only real drama was the a/c and a few sensors. Unfortunately Apexi dont make a power fc for a manual rb25 stagea, they do however make one for the rb26 stagea. Go figure. I too did the manual conversion, its a bit of a job.... you need as mnay hands as you can get..
Its fun to drive now, i've even chopped a few GTR's and they don't like it, but you do get the good one who compliments your car and say's ' i can't believe i got owned by a wagon'...........music to my ears...lol
Cheers
Gary