Apologies for going wildly off topic.
Ohhhh, they're rotax 122 engines, are you guys using the delorto vhsb34ld carbs still? If you are, is playing with the needle the right way to go to eliminate the 5-6k rpm flat/dead spot?
(don't worry, I'm not a rival kartist, I just have a couple of rotax engined aprilia motorbikes...)
And to bring it back on topic. One of the mercedes drivers will be faster than the other this year.
No, Rotax came out with the EVO kit last year and it has a new carb and igniton with electronic power valve. It runs great with no flat spots all the way to redline (14,100 rpm in DD2) and isn't very sensitive to weather changes.