Lol, if you can't handle a TII swap, then an LS1 is also outta the picture.

For real, its not all that difficult as far as engine swaps go.
You'll definitely want to stay w/ the same series motor as your car (ie.. S4 n/a --> S4 turbo, or S5 n/a --> S5 turbo). If not you're asking for a lot of wiring/ compatibility problems.

Get a motor that comes w/ harness and ECU, that way you can just pull the n/a and harness. Drop in the 13bt run the wires, bolt in the ecu and start worrying about the drive train.

You can run an n/a tranny on a 13bt, and a custom drive shaft will get you there, but by the time you buy one (unless you make it yourself) you could probably bought most of the parts to convert it the right way.

That being said, an n/a drive train can handle stock TII power pretty well, but you start modding and ......