I own a 2015 Mustang GT w/ perf pack and the driver side rear shock is shot. hydraulic grease everywhere. Can I replace the one bad shock and find the same that came with the car?

 

Rule of thumb is to replace shocks in pairs or even all 4 at the same time, but definitely in pairs. You can just order replacement shocks from your dealer or go to RockAuto.com.

 

You so both of them, doesn't matter if you have one bad. You could end up with
the other side sagging with one new, and one old. They're cheap enough on eBay
to do both. Well, unless the PERF-PAK has special shocks... Still, you should
do both, unless you're well under like, 10,000 miles....

 

you will be glad if ya do both.