Hello to all experienced Smart 451 Turbo (84ps) drivers. Drive now for 6 months my Smart Bj 2007 running time 75000km with 84ps (for 5 months an increase in performance to 110ps and for 2 months a sports exhaust of Raggazzon 62kw center). Since the beginning I noticed very strong vibrations at full gas between 2000-3000 u/min. The vibrations feel and I hear so intensely that my seat vibrates with vibrating… What can this be? Also I notice that in the speeds I lack the power (FEELING) but it just comes to me because of the strong vibrations… I am with the Latin at the end… The SC taps on the exhaust system of Raggazzon, which however can not be since it was already before the installation of the new exhaust?…. I thank for every help… With friendly greetings Hirschfelder