x6 Sq/22/B4 as indoor racer
 

I have an X6 Sq/B4/22. I want to use one of them for carpet only racing. The B4 would seem more suited to Wet. 22 as my outdoor summer car. Therefore was considering the X6 Sq as it is the least used. Is this the right idea?
Does anyone have an idea for the motor turns for a 10.5 and a good starting setup. I have never raced on carpet but could do a few pointers.

Tyres - Yellow Minispikes
Gearing - for a 10.5 (or should I put a faster motor in it to be competetive)
Suspension - Do you run the car still at wishbone level or do you try to get it lower?

Or do you just run your off-road setup without any changes and just change the tyres to mini-spikes

Thanks