2013 GMC SIERRA 2500 IS BI FUEL HAS A 6.0L V8 ENGINE AND IS 4WD. HAS POWER LOCKS, POWER WINDOWS, POWER MIRROR. AM FM STEREO. HAS CLOTH INTERIOR, TRACTION CONTROL, TILT WHEEL, CRIUSE CONTROL, STORAGE IN BACK, BED COVER, BED LINER. FIRESTONE 265/70R17. *DOES NOT HAVE BACK SEAT. *DOES HAVE SMALL DENT AND SCRATCH SHOWN IN PICTURES. 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.