Had my first race meeting with the 501 last night and was well impressed with the car.
Despite the driver being very rusty (haven't driven an off-roader competitively since 2001) I didn't make too many mistakes and wasn't too far off the pace of the regulars.
The only trouble I had was getting used to the astroturf sections of the track - as it was the first time I'd driven on such a surface. The car was dialled on the dirt section but a little too twitchy on the astroturf.
I was running the front one-way so I might try a diff next time out.
Otherwise the car was excellent, handled and steered well and was completely reliable.