I purchased a Diablo Sport tuner $385. It would not work at all for the 2008 duramax. I contacted rpm outlet which told me to contact Diablo. Diablo told me the tuner had outdated programming in it and had obiously been on the shelf a long time. I again contacted rpm. I told rpm all I want is up dated programming. When I finally got a return murchandise formand read it I would not sign it agreeing to let them keep 25% of my money. My return was sent back to me with a lie saying I did not send the return merchandise form. UPS said they delivered it three times, but rpm refused delivery. I now have a cheep tuner that will work for the older LBZ and LLY duramax diesel engines, but definetly will not work for the LMM duramax
signed
Outdated Henry