E Chassis 5" HD Intercooler N54 N55 135 1M 335 X1 (Stepped core) MAD BMWThe stock BMW intercooler is small, inefficient, and cannot keep up with the high boost levels that tuned vehicles demand. The MAD BMW 5 Intercooler is engineered to keep intake air temperatures under control, allowing your BMW to perform at its best under all driving conditions. Designed specifically for E Chassis BMW N55 applications, the MAD 5 intercooler features a high fin density stepped core for maximum cooling efficiency and improved airflow.