THE MODIFIED TURBOS In the past, Kleemann has mostly done it in the installation of compressors on Mercedes. But since the 5.5-liter AMG engine in the E63 is already equipped with a biturbo, it was necessary to follow new tuning paths. Therefore, Kleemann has, among other things, the work on modifying the turbos. The paddle wheels have been made larger, spool up faster and are able to deliver increased turbo pressure. In addition, they are sharpened so that they do not block the exhaust gas too much, but allow a good flow. The advantage of keeping the outer shell from the turbos is that you can always go back and fit a standard turbo if it becomes necessary. 
MORE AGGRESSIVE COOLING In addition, it has also been necessary to upgrade the engine's cooling systems, so that they match the extra heat that increases performance. Among other things, more of the charge air cooler is required if you want to avoid the charge air becoming too hot, which would mean a loss of power. Kleemann has also tinkered with the engine management, which in itself gives around 100 hp extra. And then a modified exhaust system has been fitted, which, in addition to contributing further to the effect, also makes the family car sound like a vicious leashed dog growling aggressively.
