4.11's
 

about how much time can i expect to shave off in the 1/4 mile if i get these?
I see them on SLP for about 240, but what else would i need, they have a kit for that too but i dont know if its just extra crap. Also, what kind of gas mileage changes can i expect? BTW, i have an M6 so about how many rpm difference can i expect? thanks

first off, let me say with an m6 i wouldnt bother putting 4.11s in a 10-bolt. the stock rear is weak as is, once you put bigger gears in there it is even more likely to break. if you did get them you would need the install kit. not exactly sure what the rpm difference i, because i forget where the rpms were in my car with 3.42s. but lets just say i use 6th gear a whole lot more than i used too, lol.

stock rear + m6 + 4.11 gears = kaboom

i see, what else would i need so i dont go kaboom? a stronger rear end? and if so what kind?

12 bolt or 9 inch

but thats some serious $$$

honestly, unless you plan on going full out, suspension, drag radials, H&C or FI with 4.11's you're just going to spin. Unless your rear-end needs to be fixed already, I'd spend my money on upgrading the suspension. Stock there are already traction issues to be dealt with before adding the gears. I looked at doing it but i drive 25 mi one way to work so don't want the extra rpms on the freeway. I think 4.11 just about make 65 mph @1900-2000rpm it's about a 20% increase i think (4.11-3.42)/3.42 ~ 20% increase.

9" rear for M6's.......

if you are planning on sinking money in your 10 bolt, you might as well hold up that ammount of money and light it with a match....

and dont you mean 4.10 gear?

thats what i thought but SLP has it as 4.11's
i guess that can wait until i get more money, but thank you guys for the input