PLM Mercedes Benz 5.5L AMG Heat Exchanger XL (25% Bigger) Cooling KitPLM Mercedes Benz 5. 5L AMG Heat Exchanger for E55 CLS55 SL55 is now 25% bigger in our XL Extra Large version. Like our standard sized version, it still mounts in stock position. Supercharged Mercedes AMG's tend to overheat under hot weather or extreme driving conditions. If you increase boost or horsepower, expect your intake charge temp to rise even further. The solution is to add the upgraded PLM Private Label Mfg. Power Driven heat exchanger. This