The sway bar made a big difference cornering, well worth the money to me. I'm very happy with the results. Also very happy with the belt tensioner, i had some slight vibration that i just thought was normal or maybe from lugging the engine at times. The tensioner took all of that out. When i had my HD's i would add accessories and sometimes the end result was negligible, i am very happy with all the mods i've made to the Spyder so far.