Difference in MB Quarts???

I have seen a couple of listings in the local paper for MBQuart PSD 213 and MBQuart PSC 213.  I'm pretty sure that the PSC means that it is a coaxial speaker, but I'm not sure what the difference is between the PSC and PSD.  If anyone can help me I'd appreciate it.

Also, does coaxial mean that I will need coaxial cable to install?  I'm trying to learn as much as I can before I run off and buy an Amp, Speakers and HU!

Sometimes I wonder why they used the word coaxial because it is very confusing and has absolutely nothing to do with coaxial cable.  It's good that you're trying to learn before you buy though, cuz not enough people do that and they find themselves inundated with meaningless information at the store.  One thing I'd recommend is checking out Crutchfield's site as they have a lot of great info on what features to look for and how to pick out products.  Also they'll tell you what fits in your vehicle.  Prices are sometimes high but it's a great starting point for information.

Now as for the MB quarts,  here's the page on the PSC213 and the page on the PSD213.  The PSD's are just the newer version of the PSC's.  The PSD's use the tweeter from the premium series, while the PSC's used the tweeter from the reference series.  I should note though that BOTH of these products are 5.25" component speaker systems, each with a separate midrange woofer and tweeter, as well as an external crossover.

I think PSC stood for "Premium Separate Components" and maybe PSD is for "Premium Separate Drivers"?  not really sure though and it's not like it really matters.