5.3 into 98 c1500 longbed

This summer I'm planning on throwing in the gen 3 5.3 in my 1998 2WD C1500 longbed that has a dead-ish 4.3 v6. I have read and reread the official thread more than once but i still need some advice (sorry if any thing has been answered a dozen times). My plan is to buy a salvage truck if i have researched this right i can get a Silverado with a good engine and trany (and most of the stuff i need) for pretty cheap, but i would like to know if this is a stupid/bad idea for example if it is gonna cost more than what it would be to buy all the parts separately or if it would to risky to trust parts out of a damaged vehicle.

I want to double check something, if i get http://dirtydingo.com/store/product_...oducts_id=1314 i wont need a new driveshaft or any more custom mounts? Also i honestly dont know alot about transmissions.... like nothing XD, so i was just gonna put a stock trany from a Silverado in it. And i'm assuming there a differance between the trany in a 4x4 Sliverado and a 2WD one, and if so can a 4x4 one be converted for a 2WD truck?

my truck is a 96 & basically the same. you can look through my build thread, link in my signature below. i also have the wiring diagrams for the 97-98. those 2 years are different from 96. i didn't use the dirty dingo mounts but a lot of guys do. if you're looking for a harness i suggest Nelson, top quality product.