I'm interested in this as well. There is some useful RB general info in the sticky at the top of this forum, but then it gets blurry on some of the details, like if something applies just to the RB26 or to both. I'm particularly interested in the RB25DET Neo (R34). Though I'm into performance, I also care about stuff like gas mileage and emissions. And supposedly the Neo engines put out significantly less emissions while retaining high power output.