MT or AT will depend on your personal preference. I opted for the MT mainly cause I wanted a manual tranny and test driving both confirmed that the MT was what I wanted. As far as the RSB, AT is 17mm and the MT is 20mm. The Aspec package does not include a beefier RSB. You can get a 22mm RSB from Comptech and that combined with the Aspec suspension will give you better handling and cornering capabilities while reducing body sway.