Hello I own and 2013 Dodge Challenger R/T 6-speed manual and was looking at the Diablo Tuner's. Which one, if any do you guys recommend. Any faults you can see with the tuner. The only modification done to the car is a K&N Cold Air Intake. I'm really curious if people see major gains with the little tuner or if it's better to have it tuned at a shop.