Yes there is a huge diffrence! 8" drivers are a hell of a lot louder and produce way more bass. If you use a crossover and hook it up to an 8"mid-bass driver and a seprate tweeter you will be amazed by the sound. I went the cheap route and got a pair of the West Marine XXL box speaker with an 8" driver and seprate tweeter for $99. Let me tell you they are funkin' loud! They are loud with the engine running full boar on a jet boat. The only draw back is that they are heavy!
These will severely make you DEAF.. @ 123DB these image Dynamics will crush anything on the water, crystal clear and no distortion. Still fitting in the 6 1/2's.. Lake vacationers HATE US