I'll try to clear up some confusion in this thread so bear with me. That is not accurate. Aluminum is fine running E85. You will not have any issues running it. I agree. :thumbsup: That would be all you would need. I will have to correct you on that. At cruise the car will only use 10-15% more fuel. At WOT is when you will need about 25-30% more fuel. It does burn cooler, but that's not 100% accurate. I have seen data that says it is 105. I have seen different results than the one single post by "black2003cobra". I wouldn't read it as the bible. In the test that state that "Heywood gives (100%) ethanol as having a MON of 89 and a RON of 107." I have seen reports of ethanol's RON is 129 (116 MON, 122 AKI). So who is correct? I would fair to side with E85 being 105 Octane. I have even seen it posted on the pumps. You won't have enough injector. That is 100% in the tune! The car will drive like stock if the tuner tunes it correctly. :rockon: Yes. It will drive just like stock if tuned properly. (I have tuned several) I agree. Return is a better mousetrap! 80's will be just fine even at 400 RWHP if tuned correctly. And Josh, just because you had some bad luck with returnless systems doesn't mean they are ALL bad. I am running a returnless system right now and the car runs like stock! I do agree that the return is the better of the two though.