I've decided to keep my car, soim going to do some upgrades soon.
How much Installed from a shop? Estimate..

 

I'm assuming that your transmission is an automatic. If you're going to do this, it will be very expensive if you have a shop perform the swap. You're better off trying to find a wrecked F-body that was equipped with a T56, pulling out the parts that you need and performing the swap yourself.

 

deff do it yourself like buffalo said VERY expensive

 

I did a mock up quote in a thread a few months back. I think I came up with 4500-6000 depending on where you lived. Finding someone willing to do it would need to be your first step. Most shops will not do this type of work because there is no manual on what needs done. You would need to find a shop that knows 4th gens inside and out.