Just my 2 cents, but you should seriously consider doing the PowerMax turbos now, which I ended up getting for less than $3k by shopping around. I would also seriously consider changing out the stock manifolds to the Full Race manifolds and studs. You will want them if you have any desire to make big power, and they do reduce cylinder pressure, which is probably good for longevity vs. tuning the h*** out of the truck with the stock manifolds.
Do it now. Otherwise, it is going to be a massive pain to do after you have put everything back together. You can upgrade downpipes, injectors, plumbing and the rest of it easily later. Turbos and heads are a massive pain to get to later.
I would also seriously consider getting the sand blaster and the POR-15 out for the front section of the frame.