depends how you feel about "authorized" retailers. You can get some outstanding deals if you are willing to forego the factory warranty. I've purchased from www.ikesound.com. They have the lowest prices of just about every car audio site. Most of these places do offer their own warranty...meaning if something goes wrong they will replace the item rather than through the manufacturer.
I've also been in the hunt for some new car audio items and used google to find various sites and online retailers...... I ended up buying some Focals from an ebay source and a JBL amp from Sounddomain.com....... some great deals if you look around.......
I use ebay mostly, but my sub amp just failed. I'm gonna go with Phoenix Gold next.. Ikesound is wacky on shipping and returns but the prices are really good.