Early Gen4 model owners have had their weak springs replaced by Glock. I believe the issue was recognized and replacments made available in the spring. If it's new at a store it should be good to go at this point. That said I'm on the hunt for a Gen4 19 myself. Almost had myself talked into a XD9-3.8SC But couldn't do it due to being infected by Glockitis.
Gotcha. This is #2 on my list then. They are #1 for repairs though. I'm sure you are filiar with them. Wheel Medic. http://www.theroundhouse.ws/Services.html
This is who I and quite a few others have used. Info in 1st post with pics. http://www.ohioriders.net/showthread.php?t=76177&highlight=just2ez He's north though, not in central OH but worth the drive for quality and price.
$550? Damn dude. Get a Glock. 8mmDale takes trades and can order anything you want. I guarantee you won't get screwed. The prices he's given me are better or the same as Vances and he doesn't buy the quantities they do. Also if you want a real world value on a weapon I'd ask him as well.
Um. Those are legal. At least I've seen more than one for various calibers. Heres one. I don't see any restrictions on purchasing. http://www.midwayusa.com/viewproduct/?productnumber=528357&cm_mmc=Froogle-_-Gunsmithing%20-%20Magazines%20-%20Rifle%20-%2011%2B%20Rounds-_-PriceCompListing-_-528357