NNBS seats bolt right in, but you're going to need to figure out the electronics.
Here is the DIY I made.
GMT 800 & Older GM General Discussion - SEATS - 99-02 Fronts - (Fix & Clean) - I tried to write as detailed a thread I could about what steps I took to make my seats as brand new as possible. Whether you want to replace the drivers side cushion, clean the seats, or repair any non-electrical...
www.performancetrucks.net
Not sure if your covers are bad. I can tell you right now, the cost of those makes it real hard to justify not just putting in a set of NNBS leather seats.
If your covers are good, your foam is most likely good, it's the thin support bars inside that break and give no support, and there is a big difference when they work properly. The frame of the seat pan and back are pretty thin, and if you're a big guy they don't hold up well.
I don't come on here that often, but I'll try to answer anything if I can.