Those speedos will work providing you use a receiver pack (LiFe 6.6v is best and you will need a minimum of 120mAh to run one race with power to spare) or a voltage booster with the 1S cell. They won't work on their own with a 1S cell. Once you have a receiver pack fitted it will all work just as it did before. Make sure that the receiver pack/booster has a switch and DO NOT switch the speedo on, just the receiver pack/booster.
The best upgrade for the Mardave is the carbon plate for the front suspension.
For GT12.2 you may not run anything that was not supplied in the kit. So, if your kit came without ballraces then you can't fit them. Both the current kits from Mardave and Schumacher come with ballraces as standard.
In GT12.2 you may change all the suspension settings including springs, damper fluid, damper parts (eg O Rings on the Supastox) castor, camber and track. If you added spacers to change your castor that would be allowed.
GT12.2 is to allow anyone to buy a kit, build it and race it without having to buy anything else except a few low-cost springs and O rings and damper fluids. If people change things like screws, springs, washers, body clips or any other non-performance-related item then that's OK.
We are feeling our way on this class, so expect anyone who pushes the boundaries of the intent (buy a kit and race it out of the box) to be asked to put their car back to kit, and the Rules to be amended accordingly. This is the class that will be lowest-cost, and to that end differentials are also not allowed.
If you've any detailed questions on that, please ask, or PM me. I hope you enjoy racing your GT12!
