Here are a few of my ideas ...

If you are putting a v8 & tranny in the truck I would most definitely update to IFS.

However if you are worried about keeping up in traffic and are on a budget some rear gears / disc brakes and a little engine work would be a good route. This way you don't cut up a cool truck!

Not so sure I would trust the cheapest springs out there ... remember you get what you pay for. (well to a point that is).

Patricks offers a lowering spring which lowers the truck a couple of inches. I know these are excellent quality springs because I had a set but decided not to lower my truck.