HX are also light, but the big thing is to go with a narrower tire. Stock Civics are 185/65x14" or 185/60x14" so I would go with 175 wide tires if possible to get less rolling resistance.
__________________
Sponsored by: KAM Racing Sports, Falken Tires, Progress Technology, Brady's High Performance, Taggart Performance Engineering, Rotora Brakes
Autocross is: 90% driver, 5% car, & 5%
CRAZY MOJO!
Autocross Help Page