Best hop-ups for my TRF501X?

[tama]

Hi,

What are the best otional parts for my TRF501X?
I think the 1-way (front and/or rear) diff, The stabilizer bars and the wide belts...

What do you think?

Also I think about a brushless and ESC to use it in competition... I like the Vector X12, but how many turns? and what ESC?

Thanks