Was thinking of adding a programmer to completly stock(engine/trans)LMM. I was going to leave stock exhaust,intake if possible, will the programmer be able to reach its potential? I had my last truck egt's set at 1250 and when towing up a grade it would always turn on,turn off,turn on, turn off due to egt temps. Thanks

Short answer....yes.

Long answer is that by you adding more power, you aren't going to see any, if not worse fuel economy because your DPF is going to get filled faster.

If you are springing for a programer, and the extra $300 and get a turbo back exhaust and reap all the benefits.

Kevin