Not as fast as I thought

[paperchase]

I love my 03 RS6. I love that it's rare. I love the handling and build quality. I love the exhaust note and the list goes on; but I'm a bit underwhelmed by the power. I don't expect it to be as fast as my Mercedes CL600 with an ECU that pushes 650hp, but the way I was dusted from a standstill by a cls550 was painful to experience. My RS6 is stock with almost 80K and has no issues that I know of. I understand that the cls550 does 0-60 in 4.2ish but based on the specs it should have been a closer race. Granted I had a passenger and a trunk full of old LPs I was moving, but still it was no contest whatsoever. My question is whether there is anything that could be contributing to a significant power loss that I might look into. Maybe a blow off/diverter valve or something of that sort. My other question is how profound an increase in power (real world power like 0-60 times) would an ECU bring. The chip in my CL600 completely transformed the car without a doubt to the tune of more than 100 hp although that tranny can handle the load. At the end of the day, I didn't by the RS6 to drag race, but I'm used to being among the faster cars on the road and, in my untrained opinion, the RS6 does not live up to the hype of being superfast. Again, I still love the car and am happy in all other respects aside from off-the-line acceleration.