I removed this resistor on my 1990 560 SEC and feel a noticable improvement in off idle, midrange and top end performance. I always run premium anyway and am not hearing any indication of detonation.

The most dramatic improvement I feel is in mid-range torque. My car lifts the front end (not the tires) almost like a muscle car and scratches both rear tires when it shifts into second gear now. It NEVER did that before. Thanks for the tip.

My next performance mod is going to be to replace the stock aged cats with some new high-flow units. I've already put in a K&N air filter, removed the kidney shaped resonators- replacing them with a short, straight through pair of glasspacks and swapped a 3-chamber flowmaster for the stock muffler. It sounds sweet, doesn't drone, is lighter and flows better.