03 SL 55, Renntech pkg Plus, ceramic headers, phenolic intake spacers 8mm wires 80mm TB 2nd cat del
I have been looking at ECU upgrades from Kleemann Renntech and Powerchip. Powerchip claims the highest increase in HP. Is there a noticable difference in performance after the upgrade? Also, is it best to stay with Kleemann or Renntech?