I looked into the Kleeman kit http://www.kleemann.dk/site and it appears to be a smaller pulley and a new serpentine belt. Their website looks, at first glance, to have lots of info, but if you dig in, you will see it is fairly generic. I resorted to corresponding with someone there by the name of Caspar Gorm, and the price quote was $2,595 Euro, which is around $3k. Really. $3,000. They claim something like 400 hp, but that is starting from the 354 the SL32 had. Since the Crossfire ECU is remapped with a less aggressive spark curve because of the lower octane U.S. gas, the realistic output would probably be around 375 hp.

The only other thing could be a re-map of the ECU. Not sure if anyone can do the SRT-6. From my Upsolute Chip upgrade experience on my first Crossfire, I would probably stay away from any SRT-6 chip upgrade unless you have 93 octane and/or live in a cool climate. The moderate pinging I experienced on the non-supercharged Crossfire engine could spell disaster for the SRT-6 motor.

There might be a K&N filter available (anyone know?), but I would stay away from this too. The 3-5 hp (hotly debated numbers, none of which you will actually feel) improvement is not worth the reduction of engine life in my opinion, and with the supercharger, it may be a reduced supercharger life as well. Also not good.

In summary, there is really not a thing you can do for more horsepower besides the Kleeman kit. At least not yet, and I am not holding my breath.