DrBlockHed

My car is stock right now, looking to do ARH 1 7/8 headers/ORY/magnflow catback, while that's getting done I wanted to change the gears.

I've read a bunch and decided that 3.90s would suit me best, I have a long commute that I drive about once a week w/ my TA, I won't be going to the track (maybe once or twice). I then read that 3.90s can't be used on a stock rear, is this correct? What would I have to do to go w/ 3.90s as opposed to 4.10s? While I'm firing away w/ questions, how much MPG loss would I incur (stock to 390/410s?) w/ a pretty much stock car?

Thanks

666ws6

iTrader: (3)

I have 3.90s in my stock rear. And I have run a bunch at the track without issues yet. I has been 5 years now and I like them. I have an A4 though. If you have a manual, most people choose the 4.10 option. I didn't track mpg specifically but i have only noticed a slight drop. Nothing I would worry about really.

DrBlockHed

I do have an M6, I was steering away from the 4.10 due to still having a 10 bolt and gas mileage

Thanks

redbird555

iTrader: (14)

I have them in mine and love em. I feel that 4.10s are just a little too short on the street for the m6 390s seem just right imo