I have the 3805 and i like it, i use it on tow setting always. The perf. is 137 hp and i tow too heavy to use that tune. I got @ 2mpg gain when i put it on. I hear people getting 1. 5-3 mpg gains on perf. Now you are getting ready to be flooded with... ... ... . get a smarty... . smarty is the best... ... . Yes there are alot of other programmers out there that are alot stronger but this is a nice programmer for the $$ IMO.