Pointing out the obvious is fine man but you may find Im the closest link when talking about the obx and 4efe combination regardless of system used. I just urge you to try a combination on the 4EFE motor yourself. Although it was a powerflow with the obx as thats all I had access to system wise at the time, it didnt go bad at all and was even better when I evened the odds by adding the 5EFE. I've always been about experimentation with my motor and Im not afraid to do it. I know people say there is not a lot of difference between 4E and 5E na but I believe there is and from now on its all going to be about 5E for me, I don't want to look back. It does seem like you are not going to get a straight answer mate, there are lots of factors and variables involved. I would urge you to try the combination that you think will work best if you can acquire it and work from there. Nothing ventured, nothing gained, all we can do is ask or assume otherwise. Joz