Well, in my case, I am probably over $15K in new or used parts thus far. Some of that was stuff that probably didn't need to be replaced but I was in there anyway.
I would have to go through a massive pile of receipts to break each system down by cost, but thus far, here is what I have done:
- Rebuilt top end of motor along with having the head serviced by a reputable machine shop. I also had the injectors cleaned and serviced, installed a new alternator, water pump, oil pressure sender and jumper wire, heater valve, timing chain tensioner and a million other little things as part of the refresh.
- All new braking system that included new calipers on all four corners, new pads, new front rotors, new master cylinder and booster. I also deleted the ABS and the LSPV as part of that process.
- New(used) gas tank, filler neck and skid plate. New rubber bits that go between the tank and neck, etc. I also ordered all new hard fuel lines but I didn't install them because mine looked fine(I still have them and will hang on to them, just in case).
- All new AC system with all new components.
- All new exhaust system from the manifolds back.
- 4 new BFG KO2 tires.
- New(used) driver's side inner and outer fender.
- New shocks.
- New(used) sunroof panel and new(used) rear slider windows.
- Front mud flaps
- New(used) rear bumper components, new flare gaskets.
- bhicks cup holder(so far, this is my only aftermarket mod

)
- Front axle components with re-used birfs
Add to that a million little bits and pieces, tools, fluids, paint and shop supplies and I would guess nearly 1000 hours worth of my labor and I now have a truck that looks and drives awesome and I wouldn't hesitate to take it anywhere my wallet could afford to feed her.
Keep in mind that many of the things I replaced or refurbished were due to rust. If you start with rust free, there is a good chance that you could avoid some of these projects, but I would think most trucks in original condition that haven't been gone through yet would still need some work on most of the systems I rehabbed. They are sturdy vehicles, but they are also complex and have a lot of parts that probably are reaching the end of their useful life.