Does it affect gas mileage? It'* not like I'm gonna be buying one anytime soon (S1 ), but I think it would be cool to know

I used to have an I-PCM. No noticeable changes. Same goes for my DHP.

Some people have seen a good increase in mileage, and some don't. I my GTPs I noticed about 2mpg gain....now my G/Fs GT lost about 1mpg.

Either way its a good mod. Just make sure you have the supporting mods for it, and you'll have a better chance seeing some MPG gains.

Agreed, it all comes down to having mods to support and as with anything else. If you keep the pedal on the floor, how can you expect MPG'* to appear increased.