Hi all, finally had the X pipe exhaust mod done on my SLK55. Also added the K&N filters to assist the breathing. Can't believe how much better it sounds and runs. Feels like some additional HP has been gained but the BIG pleasure is the sound it makes when the accelerator is pressed. What a pleasure to hear that sweet little V8 working. If you're considering the exhaust mod, by all means, do it. You'll LOVE the result!!