I have been using a W209 CLK63 for a few months now, has exhaust and software, prob the loudest 63 in SA,LOL but damn its so much fun. Can hammer that car day and night and it just goes like stink problem free - only things done in the last few months was radiator replaced and waterpump serviced. Other than that, its just brutal problem free hammering, cant say driving as the car just get driven hard alot,lol. Very very fun car to have but petrol consumption is hectic, haha