Repairing foam suround on subs

I have two kicker 10" comp subs that the foam is almost all the way off on one sub and about half gone on the other.  I thought my speakers were just blown, but after looking under my grills(fine mesh which you can't see though), I discovered I can see right inside my sub box.  The speakers have been sounding worse and worse for the past 6 months.  The past 2 weeks it doesn't even sound like subs are in the car. 

I know they can replace the foam surround on the subs for $35-50 at most speaker repair shops.  My concern is would be that I ran these speakers for so long in this condition, would I have harmed them by over exersion or something like that?  The less bass I heard, the more I turned up the remote knob on my Epicenter.  I don't want to put $$$ in subs that are going to be crap anyways.  Is there a way to test the sub, before I take it into the shop so I don't wast money on them it they are bad.  I know you can also replace the voice coil, spider, etc. but by that time I could of just about bought brand new subs with a warrenty. 

The way I see it I could spend:

$100 or so to repair both subs and pray, pray, pray that they work good.

$220 for two brand new Infinity Kappa Perfect 10.1d subs from etronics.com this includes the shipping and handling. 

I will be making a desision on this sometime this week as I want to have this working back up to par by next weekend.