Hello ThomasJ,
Based on your VIN with the digits "126" immediately following the WDB states that your car is a European model and NOT AMERICANIZED with all the horsepower robbing smog crapware that we have to subscribe to in the states. MB brochures state 238HP for the US spec. engine and 300HP for the Euro version, however, only a dyno test can reveal your particular situation. Any after market engine modifications will, no doubt, change the manufacturer's stated specs.
Others will chime in here and offer more info......I hope this helps a tad!
Gary