Probably the hardest part is trying to get the engine mounted.
After that, you'll just need the correct fuel supply, wiring harness and pcm to get it started.
I"m not sure on the gauge stuff.

GM didn't make an LQ4 in 98, but I see what you're getting at.
I'd go with a 2001 up 6.0L and those will have the aluminum heads and crankshaft that doesn't stick out. It may make mounting a T56 behind it a bit easier.