I would just wait. I don't see the RF's providing that much of an advantage over stock and you'll have to just end up selling them when you get your new speakers. If your stock sound is terrible right now though, then maybe it'd be worth it for you.
If I was you I wouldn't get them just because they are only $50. If you save up a little bit of money there is much more out there that will sound much better. I would just wait to buy your CDTs from Exige and not spend the money it is basically a waste. That $50 could get you a possible upgrade from Exige.