When I first got my bike I got a tuner for it. Other told me to not use tuners as they will destroy my bike. Later as I added more performance the original tuner could no longer handle it, so I moved up to the PC5. I have been very happy with the PC5. The canned map they gave me for my set up was warm at best and the bike did not run too well. But it got me to the dyno shop alright. Lucky for me it was running rich, so frying the motor was not an issue. but a visit to the dyno and they got things trimmed near perfect now. Plus lots more power and torque. My question, is how can a tuner ruin your bike? I can see if you use the wrong tune you could run lean and fry the motor or run rich and have crappy performance. But as for ruining the motor I need someone to explain that. The people who told me not to use tuners, told me to go TTS instead. What is the logic behind this or is it simply folklore?