15 seconds here I come!!!!

 

Good luck

 

I gained 4 tenths switching from 3.42's to 4.10's and that with a open diff both times. It would be pointless and I dont recommend driving/racing without a updated tune. Those 3.42's are gonna hold you back as far a performance unless your going SC and I would still get 4.10's then. I actually gained 1 or 2 mpg when I went to 4.10's!

 

I have never heard of anyone gaing mpg from going to 4.10's I wonder why you gained mileage.

 

maybe he does more city driving