Top swap removes everything from the top end of the L67 and puts it on the L36. Parts required are heads, LIM, SC, TB, fuel rail, harmonic balancer, and all the little odds and ends like vac lines and idler pulleys etc. You pretty much rebuild the top of the motor.
If you're not doing it yourself, do not go this route. A lot of labor. You shouldn't mod the car too much anyway unless you know what you're doing and not go trusting someone else. You need to know what's going on in there.
I prefer the swap since I'll be rebuilding the heads and it's a lot easier to do that on your desk than when they're on the engine. Plus they'll be completely cleaned (dipped) at a machine shop so it'll be like having a brand new engine. In its stock form, the 3800 bottom end doesn't wear very much so I don't have to worry about rebuilding it. Something happens, get a new one. Plus, I already know the history of this one so I prefer to work with it.
