I ran mine yesterday at the Faversham club, indoors on wooden floor. I was advised to re-gear it with a 20 tooth pinion to get the right gear ratio, but apart from that (and 40 weight shock oil) it's bog stock. It went pretty well, although completely differently handling to my DF03, it was like driving a wet fish as the back end was all over the place. It seemed to prefer lots of throttle and lots of slide rather than trying to get it to steer round corners like the 03 does. I'm definitely going to get a front 1 way for it (if I can stick the RC Champ site through Google to translate it I might get one from them, or wait til Hobby Co get them in stock) as I was talking to one of my mates who used to run a XXX4 with an overdrive front 1 way and he said it was awesome round corners. I've picked up a couple more setup tips, a couple of guys have told me to lower the top arm mounts and give the back end more anti squat to stop it squirming around when I boot it. Any more setup advice for driving on polished wooden floor, bearing in mind I prefer my cars to drive where I point them rather than sliding around like a demented ice skate?
My best run with the DF-03 was last week when it was sticking to the floor like glue, and it was actually going where I told it to rather than the 501 which I was struggling to keep pointing the right way at times.
By the way Elliott I'm running GP4300's in my 501, and all I had to do to get them to fit was chamfer the sides of the battery slots slightly. They fit in nicely now.
-Steve
PS I'm fairly sure the spur gear is that funny Tamiya 0.5 "metric 48" pitch as mine was nice and quiet with the kit supplied pinion but when I geared it up I used a TIR 20t pinion and it sounded like an angle grinder driving around.
I've found out that there's an 84 tooth spur available for the B4 which should fit straight on, but that would mean dropping the pinion gear down to about an 18t for me. Shouldn't be a problem as there's quite a lot of movement on the motor mount towards the spur but not much away from it. I wonder if Tamiya will release extra spur and pinion gears for this model. Unfortunately the 0.5 pinions they do for the DF-03 only go down to 23t which would way over-gear it for where I race...
