Mercedes-Benz's $5950 AMG Development package stretches output from 451 hp to 481 hp, and the additional 2.2 liters of displacement over the BMW gives the C63 an additional 148 lb-ft of torque. That's an absolute boon for daily driving, but on the track, we're playing at the top end of the tachometer, and the BMW keeps up while humming happily and aggressively so close to its 414-hp peak at 8300 rpm.
The C63 tops its massive torque with an intoxicating exhaust note, something that absolutely enchants Zamberlan. "To me, it's so unexpected that the Mercedes would sound better." The M3's exhaust is decadent as well, but the graceful crescendo is more like that of a high-strung racing car than the deep, rowdy fracas of the AMG. Our M3 also emits a disappointing heat-shield rattle akin to what you'd expect from a modded mid-'90s Honda Civic every time it takes off from a stop.
Peering through the passenger window, Zamberlan calls out the BMW's nondescript cabin: "That does not look like a $60,000 interior." The Mercedes seats also provide better lateral support than those in the M3, particularly from the bottom-cushion bolsters, reminding Zamberlan of the stock König buckets in his R32.
"I just felt comfortable in the Mercedes, period," concludes Zamberlan. "I would get more out of it faster." And what about that automatic transmission? "If I'd driven an M3 with a manual, would I change my mind? I don't know, but I will grudgingly admit that the Mercedes' seven-speed auto was very, very good."
"If every day was a track day, I'd probably go with the M3 just because I'm fairly positive that, given time and familiarity with the limits of both, I could post a faster lap in the BMW," Zamberlan suggests. "But in the real world, I just connected more with the C63 than I did with the M3, and while the Mercedes' ultimate limits may be slightly lower in the hands of someone far more skilled, I enjoyed it immensely on the track."