I am considering putting a converter in my car.I drive my car apprx.700 miles a week.It's a `02 1SC Z28,A4,2.73.I don't race at the track but I like to tear it up on the street.What converter would be the best considering all the driving I do.3000,3200,3500?????????What converter gives the best bang for the buck?how much will it cost?I can do the install myself.All input appreciated.