If you have a SLK then you don't want the C32 intakes. They are designed different because of the restrictions out front. Get the single from NW that is designed for the slk. That's all the power you need for now, and a dyno won't show the NW intakes true performance because there is no air being forced through as if you were driving with real air coming at you. Just search youtube for the crazy video where they use a leaf blower on the intake while on a dyno and gain crazy hp.