Everybody remembers how fast (and successful) the ex-Duralast truck was. Rumor is the super-secret, ultra-exotic material used for the suspension was a new rare-earth metal, (it doesn't appear on the periodic table of elements), it was developed in the cold war by government researchers sworn to secrecy, hiding in Area 51. The code name for this stuff was "unobtainium".
Another secret: Dan and Dave are actually twin cyborgs with different heads! Duralast downloads the map into their hard drive before each race, while each 'borg features nightvision and speed sensors built into their heads. The GPS antenna on the roof is just for show. And that's why they win!