I bought a slightly used '01 model around August '02. The truck was nice and I modded the exhaust and put on a Juice box. The truck ran like a scalded dog. Unfortunately at 70k miles the injectiom was toast (not because of the Juice, because of a bad design.)
The '01 and '02 LB7 engines have the fuel supply lines ran underneath the valve covers and hooked to the injectors. Well from what I"ve been told by the shop, I had several of those stainless steel lines rusted off at the injector. To make a long story short, I had 8 new lines, 8 new injectors, and a new HP fuel pump installed and it cost me $100 for the deductable. I"ve also read that the culprit is the fuel filter that does not filter out enough particulates adn eats up the Bosch hardware.
I've heard that this is a fairly common problem on the early trucks. However, my uncle had a '01 with 135k and a '02 with about 160k on it and they never had a day's problem. These are farm trucks and are used hard and both of them ran great. So I dunno.
From what I've gathered the '03 trucks started getting right and by '04 they were pretty much bug free. But I've been out of the Maxi Pad loop since '03 so I can't say for sure but I would own a '04 and up if I was buying.