That "seems" like high mileage but forum members regularly report 200-300k miles. The original owner (owners?) could have installed a cold air intake and smaller pulley just for some additional hp. The real question is for what was the car used...street racing, drag strip, or just a fast grocery getter. Agree about 1) seeing a service history if available; 2) professional inspection by someone who knows the SLK-320 (also AMG) platform.