IF you have longtubes, hahahahahahaha..... Honestly, it's tough with longtubes especially the right side.
IF you have stock headers, you will be fine, it's a walk in the park. The dealer carries them cheap...like 29-33 dollars each. Poly's are a waste with how the design of 99-06 mounts are. They are strong.
I have bbk lts and the driverside was hard. When installing headers a couple of times i think i cracked my heater core .i now unhook hoses before lifting . My long tubes hit body when lifting engine. I use a come along and lifted engine that way for more room to work