We just got 278 Crank HP out of A C-class yesterday with a torque curve flat as a table. Mods: UD Pulleys, Headers, Injectors, Intake, and a full dyno tune.

The full tune gained an average of 16 RWTQ throughout the entire band and a little over 7 RWHP from 3k up.

There is a lot to be done with these engines you just have to realize that you are working with a 3.2L v6.