I am currently scavenging parts here and there for the 3.5 swap and I was wondering, which would be the best ECU to use? I know the difference is microscopic but I want to get the best tuning.

2002-2003 Altima 5-speed MANUAL ECU (since I am keeping my 1995 5-speed tranny)
2002-2003 Maxima 6-speed MANUAL ECU (Hp is a little higher?)
2004 Maxima (Hard as hell to find) 255 HP / 265 TQ instead of 246/255.

I am pretty sure all of those ecu will fit on the same wiring harness/gauge cluster. If you had the choice, which would you get?

 

I dont know about those stock ECUs but any of them with Technosquare's L-spec flash plus either SMT-6 or SAFC-II should work quite well.