Another question for truckers about a diesel..

I don't have any experience with the aftermarket add ons but just sold a 96 Freightliner with 428,000 on it with nothing but general oil changes done to it in the time we had it. The only real issue we had were some of the gauges working intermittently and having to make some ramps on the inside of the doors so the windows would go up. After awhile the doors get a little distorted and the bottom lip of the window track hangs up, preventing it from going up all the way