Is there anyway to make a 6.5" speaker fit in a 6.75" opening - Is there like a mount or something the car audio places have that will work or am I a complete idiot?

 

um, a pirece of mdf will work quite well. made into a speaker ring, its like an adapter you can make things fit in odd places with enough mdf. so no you are not an idiot, just tell them whats up and try not to get ripped off :P