A 1999 Passat would have the 1.8t AEB engine, not a 2.0T.
Look up and do some reading on the following...
Sludge, synthetic VW spec 502.00 oil, Big Kahuna oil filter
Control Arms
Water Ingress
Timing Belt (sounds like yours is freshly done)
ABS Module failure
Turbos don't need to be rebuilt unless they're broken. A rebuilt turbo should have the rotating assembly balanced. If your turbo is shot, it's a good opportunity to upgrade to a larger one (if you're looking for more performance). The K04-15 is the next size up and bolts right in between the existing exhaust manifold and CAT. You'd want to also get a new tune written for that size turbo on that engine. GIAC and some others have off-the-shelf tunes written for that specific turbo on that specific engine. Depending on the tune, you may also need additional supporting modifications (injectors, intercooler, exhaust, fuel pressure regulator). There are also bigger turbo options.
Rear shocks/springs are pretty simple to change out. The fronts are a bit more involved. Do some searches for the procedure. There are some DIY threads floating around. If you change ride height, you'll need to loosen and re-torque all eight inner control arm bolts with the car sitting at the new height. If you don't, the inner control arm bushings will be under a constant pre-load and fail prematurely. Any time you change ride height, alignment will be effected. Caster is not adjustable. Camber can only be adjusted by shifting the sub-frame from side to side. What you gain on one side, you lose on the other. The best that can be done is to make both sides the same. There are after-market adjustable control arms (expensive) that will give you more adjustability. Toe is the one thing you can adjust.
If your control arms need to be replaced, do it at the same time you do the front coil-overs.
Look up and do some reading on the following...
Sludge, synthetic VW spec 502.00 oil, Big Kahuna oil filter
Control Arms
Water Ingress
Timing Belt (sounds like yours is freshly done)
ABS Module failure
Turbos don't need to be rebuilt unless they're broken. A rebuilt turbo should have the rotating assembly balanced. If your turbo is shot, it's a good opportunity to upgrade to a larger one (if you're looking for more performance). The K04-15 is the next size up and bolts right in between the existing exhaust manifold and CAT. You'd want to also get a new tune written for that size turbo on that engine. GIAC and some others have off-the-shelf tunes written for that specific turbo on that specific engine. Depending on the tune, you may also need additional supporting modifications (injectors, intercooler, exhaust, fuel pressure regulator). There are also bigger turbo options.
Rear shocks/springs are pretty simple to change out. The fronts are a bit more involved. Do some searches for the procedure. There are some DIY threads floating around. If you change ride height, you'll need to loosen and re-torque all eight inner control arm bolts with the car sitting at the new height. If you don't, the inner control arm bushings will be under a constant pre-load and fail prematurely. Any time you change ride height, alignment will be effected. Caster is not adjustable. Camber can only be adjusted by shifting the sub-frame from side to side. What you gain on one side, you lose on the other. The best that can be done is to make both sides the same. There are after-market adjustable control arms (expensive) that will give you more adjustability. Toe is the one thing you can adjust.
If your control arms need to be replaced, do it at the same time you do the front coil-overs.
