As said you could have searched for the answer to this and found your questions answered.

 

The cost to do that will be about what $500 at minimum especially if your going to pay someone to do it. Its gonna save you a couple MPG. Is all that really worth it? I think not.

 

actually I'm about 90% certain there's a few AT guys that'd be willing to straight up trade for his 3.5 (assuming LSD). so then he's just out the 100 bucks in shipping, if he can't find a person locally...and this is a job that's easily do'able by many "DIY mechanics".

 

It will takeabout an hour per car to swap it out, i say go for it.