Acceleration will be a bit less although the difference isn't as big as you might think and also not that important. The lower weight improves handling to such an extent that you simply get more corner speed. So it is mid-range acceleration that counts more. Besides, with a 3.5 brushless and 6 cels you have way too much power to truly use anyway.
Run time has become a bit of an issue in the 5 cel world. On larger tracks a 3.5 really comes into its own in terms of acceleration and speed. The car has so much speed and is so easy to drive due to the lower weight that it is a blast to run. But... with all that fun it is sooo easy to use the throttle finger a bit too aggressively and drop a minute or more of runtime that you can suddenly come half a minute (or more
![Wink :wink:](./images/smilies/icon_wink.gif)
) short. In the GP3700 days I would have said that I felt that was part of the charm. In 12th scale and PRO10 we used to have that challenge too and it was part of the challenge to be very fast AND make runtime. However with the current crop of IB cels which drop performance after only a couple of runs that part is less fun. But then we had problems making runtime with 6 cels too with used IBs.