I bought a new 2010 lexus is350c yesterday and im looking at getting the f sport exhaust for this car. I traded my 2008 evo x in on this car and the buschur racing cat back i had on that car blew soot all over the back of the car (car did this with factoy cat still installed). With the is350c being a convertable with white interior i am curious if the f sport exhaust will blow soot all over the back of the car and possible get into the back seats with the top down. Has anyone had any experience with this system? Any help would be appreciated. If this exhaust will cause the car to spew soot are there any aftermarket exhausts that will not? Also will running a mid pipe make a difference? Thanks in advance for any help.