Thanks.

You can look back and search for details, but in a nut shell:
1. ECU mod - 10hp
2. new exhaust - 5hp
3. Kleemann supercharger - 90hp
4. underdrive pullies (UDP) - 10hp
There are a number of aftermarket tuners that you can go to. However, there are not that many options for the C240. IMO...the cost is too high to get not that many HP. Cost/benefit is not worth the extra money. UDP for $500-600. Kleemann supercharger for $9000. New exhaust $700 - $1200. ECU $1000+. And everything you do has warranty issues - voids certain parts of the warranty. If you have alot of money to spend to modify your car and to pay out of pocket for possible voided warranty issues...then there are options out there. If not, save $$$ and get the C32.

If you can be happy with 20hp (a 12% increase) I would try shtatc's #4 and #1, in that order.

... then, opinions on this site vary on their effectiveness (from positive to witches' brew advertising hype), but you can also add a set of K&N filters too, and see if that adds something (maybe extra mileage would be OK if not hp).

Beyond this, shtatc is right. You start to rack up some real bucks for not much gain compared to buying a C320 or C32.

Thanks for all the tips Guys..