I believe you will be disappointed greatly if you replaced your Quattro with a V8 RWD Benz.

Maybe it's just my opinion, even with Michelin snow tires, my 400E is most dangerous car I have driven on snow and ice, it has way too much weight on front wheels and leaves little to the rear, and the V8 has too much torque for rear wheels to handle.

On snow and ice, because of too much weight on the front, the front end has very good traction, it never plows in a turn, it has large amount of understeer before loss of traction in the rear, it can suddenly turn into oversteer even with moderate of throttle, it is the lack of traction at the rear makes it a king of oversteering.

We have 5-6 months of winter here, almost half of these days I drive on snow and ice, and I have driven other rear wheel drive cars on snow/ice, none handled worse than 400E, next winter I will make my life better.

I have never driven a CLK500, but it shares some similarities with 400E.

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99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.