What's the difference between the level 1 and level 2 kit? Besides the extra $2,000 pricetag?

The level 2 version of this BMW 328i Supercharger system brings you car to another level, boasting a large front mount air to air intercooler and comes complete with all piping and hardware required to make this bolt on application work. This upgrade increases your car HP an additional 25-40HP over the stage 1 system. The stage 2 upgrade also includes an new high performance fuel pump to help deliver the necessary fuel. With the reliability and performance of an intercooled system along with our perfectly tuned software this system is a must for the true enthusiast looking to bring their M3 to new heights.