First welcome to the website!
It helps people to be able to answer your questions if you list more info on your Av since sometimes answers can be model specific. On suspension do you have a stock LT, or Z66, Z71 (yes they made a 2wd in second gen Avs) or even an LTZ suspension? It also depends on whether you are talking body lift or suspension lift and how much do you want. There are many threads discussing this topic if you take time to read some of the old threads you may find part numbers and photos too..
It also helps if you keep to one topic in each thread that way those who have knowledge can find your question.
As far as water leaks are concern look in the problem or maintenance sections for boards on fixing leaks. If you do a word serach on water leaks you will find many threads on the subject with various answers depending on where the leaks are occurring.. In general look at adjusting the bed panels, lubricate the rubber gaskets and if needed put on a silicone sealer to help secure the gaskets.
Good luck.
