800 motor low altitude porting

I have a 2009 M8 that I am thinking of getting porting done but would like to get some feedback from other members that have had it done and also ride low elevation (0-5,000'). Who did the porting and how happy are you with it. I have looked at SLP (currently testing for low altitude), RKT, Speedwerx and Terra Alps. Most of these companies run/test at higher altitudes than I ride at and I am sure that some others on here faced the same question. So lets here from the other low altitude riders (m8,CF8,F8). Thanks for your response.:beer;