RS CT9A EVO8/8MR/9 4G6370020 AM103 The engine output increased nearly in the entire speed range. The improved boost spool delivers increased throttle response across the whole RPM range. The unique intake sound, which cannot be expected from the stock, accentuates its sportiness. Installing this product does not effect on the stock feedback; therefore, ECU resetting is not required in order to use this product. (Some vehicles may require resetting.) LANCER EVOLUTION CT9A