beefing up my suburban.. any ideas?

Maybe you guys can help me. I have a 1998 1500 chevy suburban with a z71 off-road package and 4x4 drive. I'd like to beef her up to at least an three quarter ton capacity and need to know what I can do. I get a lot of conflicting answers from other people and figure you guys can give the best answer to me. I was thinking of replacing the rear axle with a three-quarter ton one from a heavier suburban, but want to know if it's an easy swap in and out or if there are things I need to do. And also add heavier springs or helper springs. Also, it has a z71 package, what is that exactly? what do I have with it compared to a regualr 4x4 set-up and would a different axle mess with anything? I think I have the 4L60 for a tranny and the heavier one is the 4L80, but not sure and need to know and also to know if this tranny would be also an easy in and out as it's usually found in the three quarter ton suburbans. Lastly, what can I do with the vortec V8 that is in it to make it better all around? Thanks!

Bear Fullerton
scaramasax@aol.com