I'm looking into gettin 3.73 gears and the site I am ordering from is mustangtuning.com and they says that an extra master bearing kit is recommended for cars with higher mileage. My car now has a lil over 135,000. Do I need a master bearing kit? I'd prefer not getting one, don;t want to spend the extra $90.

 

go for the bearing kit. with that kind of mileage, you'll ruin a new gear set using old worn bearings, so spend the $90, it's a necessity!

 

All depends on the shape of your rear end....