Just use an open-ended wrench (can't remember what size they are) or an adjustable wrench. They just unscrew like any other nut. If you have a ratcheting wrench (dogbone) of that size, it would probably be best. That way you aren't constantly having to reposition the manual wrench after half a turn.
Sent from the future.
2012 Kona Blue 3.7L V6:
Borla LT headers, O/R h-pipe, Borla S-types, 3.73 gears,
Steeda adjustable UCA w/ mount, BMR LCAs, Airaid CAI,
LCA Relocation brackets, AE driveshaft, GT 80mm TB,
Black 18x9/10 2010 GT500 Wheels w/ Nitto NT555s,
Eibach Sportline Springs/shocks & Koni STR.T Struts