I've been looking around and have seen mentions of this rather violent hesitation that happens shifting out of first, but couldn't find a full thread. It seems that the car will do it more often if I start with full throttle and begin to lift before the shift. I can't get it to really do it on command, not that I want to- but its ugly when it happens.
Anyone know the cause? Remedies? I have a Eurocharged tune in the near future and am thinking about Sprint Booster- will those help/worsen this?
Thanks & Happy Monday!

Do you mean that it gets hung up in first gear and over revs when shifting into second? Mine sometimes does this.

Is this only happening in "M" mode?

Mine does this in S mode. It will buck hard like it hits a limiter before jumping to second gear. It seems to faceplant instead of shifting up, then will shift after it embarrasses me sufficiently. I feel that it almost never happens if I keep the car floored (rarely can do this without seriously topping speed limits) The shifts feel great at WOT - issue doesn't seem mechanical, 45k miles

Similar thing, 1-2 intermittent jerkiness, but only after hard driving and then trying to drive like a sane person. If I drive normal for a while, it seems to go away...so my guess is software

I have the same issue. I only use S mode, have yet to really try out M mode. But it does happen in S mode from time to time. Only when I am giving it full throttle and then backing off bit, it seems to hesitate to shift into second.

Well, I'm happy that my car isn't the only one. I read somewhere that Sprint Booster helped alleviate this. This seemed possible to me, since it micromanages throttle input and behavior. Can anyone confirm this?
I think I am going to install SBII regardless once I have my Eurocharged tune.

Please let me know the results, maybe I will try that out. It seems that when this happens it revs to the rev limiter and falls on it's face until it shifts to second.

I created a thread awhile back in regards to the same problem. I also read a forum back in the early 2000's about the W210 55's doing the same thing. No one has really come up with a fix for this it will do it at full throttle in C mode or S mode doesnt matter what mode your in the car will kick down to first regardless. M mode will slam into the rev limiter and stay there until you shift it with the stick or the paddle. It might be early stages of a conductor plate failing, speed sensor not being able to read RPM signals I have had speed sensor codes come up in my car in the past...