It depends if you will be racing or just driving it at home?
Are you located in the US?
Most popular classes in the US for racing are 13.5 Rubber for carpet and asphalt and VTA which uses the 21.5. I would also recommend Lipo batteries if you can swing it.
Sponsors: Awesomatix USA ~ Roche USA ~ ORCA ~ AVID Bearings ~ Team Powers USA
TQ Wire ~ ProtoForm ~ BSR Racing Tires ~ 2mm Design
5280raceway.com [Operated by - Colorado On-Road RC Club]
MILE HIGH INDOOR CHAMPS April 20-23rd 2017 @ www.milehighindoorchamps.com