Questions for fellas with ls swaps

[Chevyllac]

I picked up a complete set up from a 2004 Tahoe. It comes with the 5.3 engine, 4l60 tranny (w/ transfer case) computer, and wiring harness. There is this guy that I found at a local car show that does engine swaps on c10's and he says he can drop the engine and rewire the harness and make it work for $1500, it will take about 1-1.5 months. My buddy was telling me that we can order a wiring kit from painless or PSI conversions and we can do it ourselves for half the price. Is that correct?? also will I need a new drive line and radiator?? thanks for any help.