Continuity mistake: When in town, the boys see Enos coming out of the courthouse. They go to get out to get Granny Annie, you see Bo in the driver's side. After they see Roscoe and take off, they do the "skiing" (driving on two wheels) thing. When the General Lee sets back down on all fours, you see a blue shirt in the driver's window, suggesting that Luke is driving.
Audio problem: In the Boar's Nest, when the Oak Ridge Boys are singing, you hear a familiar "Yeee-haw!" This is from Bo, and you hear it now and again, even when you see Bo in a close up, and his mouth doesn't move.
Continuity mistake: When the Dukes meet up with BB, they come from a side road onto the main road. When the shot goes in to a close up on BB, you don't see a side road. And half the time, you don't see any dust kicked up by the opposing vehicles.
Answer: Various reasons, but mainly to drive the Dukes out of Hazzard County because the family have been foiling his schemes since his and Uncle Jesse's bootlegging days.
Captain Defenestrator