eBay for stock speakers? They will fit directly. I may be able to get you custom 2 ohm 6x9s and 6.25" speakers, but custom adapters are probably needed to fit them to your vehicle.
I understand the stocks are a 2 ohm speaker but have you tried running a 4 ohm set of speakers yet? Just curious... If it HAS to be 2 ohm and you're on a budget - look for some used Infinitys, a lot of the kappas are 2 ohm...