Originally Posted by B00t13g
On carpet a spool works better. I ran a gear diff up front with putty.
I would agree with this most of the time.
I was a big advocate of the gear diff in the front, the mechanics behind it just make so much more sense than a spool.
However, on most tracks a spool still is slightly quicker and slightly easier to drive.
I do find it is track specific though, if you need more initial steering on a very tight track, a gear diff will be quicker.
Bare in mind that i run either 13.5t or 10.5t boosted. In 17.5t blinky, a gear diff may give even more benefits.