As far as HP and other things that some of you are concerned about with Fuel injection, the higher ALT vs lower - the higher will give you better fuel MPG and I found that in a turbo / S/C vehicle I had more HP. at higher, More air less fuel (better MPG). with many Vehicles having anti knock systems you don't have to advance your timing to get more HP. Have had Turbo's, S/C and regular fuel injection vehicles in H/A cities and states and never had a problem. Now if you had a 1971 VW Super beetle with regular Distributor your screwed, been there, done that and was not a happy camper!!!!!