Your performance loss is either bad plugs, bad cap, bad wires, clogged injectors, bad ovp causing limp mode, or the most likely the eha is outta wack. If you got a dwell meter test the car at idle and 2500. Just plug the positive wire into the number 3 socket on the right fender wall next to the abs module. It should read somewhere between 45-55 at idle and 40-45 at 2500. My car with the 2.6 m103 likes 52-54 at idle and 42-45 at 2500. My car goes like a bad outta hell. My benz didn't want to start when it started to get cold and somehow the mixture adjustment got outta wack again. I check that mixture adjustment every six months. You electric draw problem I would pull the fuse for the seats and see if that stops it. I have seen quite a few of these cars draw electric from a bad seat motor. If that dosen't help pull all fuses except what you need to run the motor and work backwords putting a fuse in at a time and check current draw. The abs light could be a faulty speed sensor (there a magnet pickup in the front hubs). Just check that the sensor isn't gummed up. If not that then your abs module might be acting up. I don't remember how to test that thing. Anyways good luck.