Add to the list: Check for excessive blowby by removing the oil cap while engine is running and warm. I would look at a few PSD's to get an idea of what you should be seeing. Check for broken exhaust manifold bolts at rear of manifolds which would indicate previous high EGT's. Check for chipped or dusted turbo blades by removing duct at turbo, do this especially if the truck has an aftermarket filter such as a K&N or an abused filter. Check for worn balljoints by jacking up one side of front axle about 2 inches of ground, place a long prybar under tire and lift up on truck while watching balljoint play. A PSD can set you back a few bucks if you select the wrong one so take your time and make a wise decision. I looked at 10 used 1999-2003 trucks with around 100K on them before I felt comfortable with the 2000 I purchased. You can find some good deals on these due to the fuel prices.