Well for starters th 6 1/2 speakers are components, as the 5 1/4's are co ax setup's
-------------
2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
The more expensive driver, the MClass component, has a few different upgrades.
1) Higher quality crossover, bi-ampable
2) Rubber surround
3) Better gasket design
But by far the best part about the speaker for sound quality is the nice silk tweeter. Fabric tweeters, like silk, are usually smoother sounding.
I have been very impressed with the MClass components when I've had a chance to listen to them.
You should try to listen to them with your favorite music at the store and see which one you like the best.
-------------
New Project: 2003 Pathfinder
Well the 15-MCSYNC5 5 1/4 are the multi Sync set from memphis....Meaning that the speaker can either be coaxial or a component set...The tweeter in the middle detaches and can be mounted as a satilite speaker....I have this set in my rodeo and they sound awesome..but they do need to be amped to get maximum performance...
The second set is simply the component set...
Coaxial means that the tweeter and the mid driver share a center pole where the tweeter resides....a component is a set like the second link...The driver and the tweeter are 2 seperate speakers...
The advantage of using the component is that most cars factory speaker location is at your ankles and your ankles dont have ears....Highs travel in one direction bass radiates....So if the tweeter is at your ankles you are not goin to get the full effect of the speaker...With the components you can mount the mid driver in factory location and then put the tweet up so you can focus the sound to your ears and get the full staging of the speaker...
-------------
Making the World A Louder Place