Savage42 I just put a Ls1 in my car. It took me 4 weeks to do the swap, this is spending a few hours a day after work. It can cost you 10-15,000 if you do not do the work. I do not have a shop, just a garage.
This is my cost
Ls1/4l60e $2500
Drive shaft $200
Radiator $200
Fuel system $400
Header $700 you can use stock manifolds--they will fit
Exhaust $200 do it yourselfe or 300-600 at a shop
Mounts $free just make them
Air intake $200
It cost me about $4900 for the swap and it could of been less if I used the stock headers. The Ls1 swap is a very easy swap, it takes about the same time that a LT1 swap takes.