I am going to be getting my 4:10's installed soon and was wondering if it will be beneficial to also put in a Trac Loc? How would that help me for autocrossing?
You wouldn't want a true locking differential...they are great for the straight-away, but not the best thing for going around corners!!! As triggz stated, the GT comes with a limited slip differential.
I will also be installing 4:10's soon and was wondering what else will be needed for the install besides the gears? Will I need bearings and seals for a 30K mile car?
A trac lok would kill your ability to autoX. You wont have a limited slip anymore so your rear wheels will turn the same around turns. If you had this your rear end would skip around turns. This is strictly for drag racing cars only.
I will also be installing 4:10's soon and was wondering what else will be needed for the install besides the gears? Will I need bearings and seals for a 30K mile car?
With 30K on the dial, I'd certainly consider having the bearings replaced. Ask your installer for his opinion...but if the additional cost is minimal and in your budget, I'd go for it.
Also, I'd recommend a high quality gear oil, such as Royal Purple. And don't forget the bottle of friction modifier.
I will also be installing 4:10's soon and was wondering what else will be needed for the install besides the gears? Will I need bearings and seals for a 30K mile car?