Hey Larry,

I'm actually not running the 12X. I was just asking for information to help Juan out at the carpet nats. I'm running the OD car, but I can tell you what i've found is different from carpet to asphalt setups.

Bigger tires and a bigger split between front/rear diameters. I'll usually start at 1.90" rears ant 1.75" fronts, and start with purple fronts and magenta rears, then go to magentas if I need more steering.

Thinner dampener tube oil. My car uses the CRC tubes with the ridges, so I use 1-3K on carpet, and drop to 100wt shock oil for asphalt. This seems to lock the back end of the car in and make it less twichy.

Slightly stiffer center shock spring. Either a silver or a blue.

I haven't done anything with the 17.5 brushless yet, sorry. I just know you need to gear them rediculously tall.