It comes with the map. I don't think it is any kind of bull. It is a guide to do it at home. If the lt's did not have the power valves everybody would just be going with gokart/rcplane/nominal porting maps anyway. Wether we know it or not the gokarts and RC engines have been there aswell and the porting numbers do not change because the math is the same. Except there engines come apart easier and the parts are cheaper......
Im not into gokarts or rc engines im just saying.....What im saying is, we are all confused about LT porting except for a few people, and we have no dyno's of the lt250 to back it up.