lebewohl wrote:I'm keeping the stock head unit. And yes, I have the sedan (2009).
Well, this is probably a first for me. I don't normally recommend this brand, but at your price point I think it might be the best option:
JL Audio J2 320.4
The reason I don't generally recommend JL, is they tend to be a bit overpriced. But, compared to the other options in this price range, they are about even for specs. If specs are all the same and price is the same as well, I'd take JL over a lot of those other brands.
Also, there is a member here who goes by Broadfield. He pops in every now and again. He works at a shop in Normal (definitely not too far from you). I believe he carries JL stuff, and he usually can get a good price for people on these forums. You might want to try to track him down. If I see him posting on here, I'll send him to this thread. He may be able to get you a good price on that amp, or recommend another option that would fit your needs. This is his user profile which has his email address.