SX3 Help

[Skidmark]

Hi Chaps,

I've now completed the build on my SX3 and have some question relating to gearing and overall vehicle weight.

First of all can someone please let me know what the minimum weight your able to run the car at within the rules?

Secondly I would like a recomendation on what tooth pinion I should use?
I've list what I believe is the relevent information below.

SX3 as per kit and instruction.
Speed Nosram ISTC
Motor Speed Passion 7.5t
Tracks I plan to race at. Eden Park, Stotfold, Hinckley & Coventry.

Hope someone is able to help.

Cheers