I have a 2001 7.3 ccsb 4x4..I have enjoyed mine.I had the trans rebuilt with 105,000 on it,was slippin a lil.Other than that ,nothin major,just what I would consider routine fixes.As for the mileage,that will vary from the warmer time of year and the colder time.Without my programmer,with the 265s (before 285s) and no mods, driving like grandpa on sunday@65 I can get roughly 20mpg on realtively flat area driving.Now with my programmer and 285s and listed mods,at the same speed I can get around 22mpg.Hope this helps.