If the water outlets in your rocker panel are clogged up, you should be able to hear the water flowing through the threshold every time you accelerate and brake. You can check the water outlets in the rocker panels by poking a thin steel pin through the holes in the rubber. If it is clogged up, you should immediately see water coming down...
I have posted on this problem in the SL-section as well.
good luck and greetingz,
with a minor 600+k