I've been thinking a lot about the harmonic balancer, and I still can't rule it out as a cause for the failure (might have played some role), on the other hand I run the 16v also without one for a long time, rev it to 8000rpm and had no problems what so ever. However just to be on the safe side and rule it out as a problem I think I'll keep it on this engine and try to get MS ignition running with the stock three teeth on the flywheel.

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190E 3.0-24v (M104 980) turbo @ 0.8 bar
1/4 mile: 2.483 / 13.540 / 175.17 km/h (street tires)