I have a 2000 Mustang 3.8L 5speed and i was wondering which gears i should put in it. I am kinda new to this and i have heard people talk about 3.73's and 4.10's. I was wanting to put them in mine but i wasn't sure which one's would be best for my car. I really appreciate any help. And one more quick question. Where can i go to get these installed and about how much would installation be?