2013 GMC SIERRA HAS THE 6.0L V8 ENGINE AND 4WD. IT FEATURES MANUAL SEATS, POWER LOCKS, POWER WINDOWS, POWER MIRRORS, AM/FM STEREO, TILT WHEEL, CLOTH INTERIOR, TRACTION CONTROL , CRUISE CONTROL, CAMPER WORK BED WITH PLENTY OF STORAGE. CLEAN TITLE 69,228 MILES FIRESTONE 265/70R17 TIRES EQUIPPED WITH A BI-FUEL CNG FUEL SYSTEM. IT RUNS ON COMPRESSED NATURAL GAS OR GASOLINE. A PREMIER ALTERNATIVE FUEL CONVERSION THAT IS EPA APPROVED. EXTREMELY CLEAN-BURNING AND EFFICIENT. THIS SYSTEM NORMALLY RETAILS FOR 13,500 INSTALLED. THIS SHOULD QUALIFY FOR A TAX CREDIT OF $1500 FOR OKLAHOMA CUSTOMERS.