I have 06 m7 with a 153 challenger track. I reversed the track because the lugs where bent over a good 1/4 to 1/2 inch. They have pretty much straightend out. The track hooks up real well reversed (no big surprise). The question is will it hurt anything if I keep the track reversed? I know that the attack 20 is fine reversed, just wondering if that applies to the challlenger.