HCA, I'm going to assume you made a typo ($5 but meant 5k?) as you can't buy any of their high end speakers for $5 (not even the crossovers or speaker wires they come with sell for that cheap
)
For a 2 way front stage (midbass/tweeter) the only brands I can see reaching 5k would be the Rainbow and maybe the Focal Be. Dynaudio and Morel will not cost you that much (just for equipment) but are considered higher end and cost more. However, if there are higher models than the Morel Elates/Supremo/Piccolo and Dynaudio Esotars/Esotec/Sytem GT then I'm all ears in wanting to hear about those.
Here are links to them:
Dynaudio
http://www.dynaudio.de/eng/auto/esotec/242gt.php
Morel
http://www.morelhifi.com/index.html
There are many brands out there that sound good and don't cost a lot, but there are also the "higher end speakers" that cost more and are suppose to sound better. How much you want to spend does play a factor in your speaker decision.
I will agree with HCA in that it's not always about the speaker brand you chose but how they are positioned/placed in a vehicle and how well they are tuned to that environment that can make or break a sound system.
For example, speakers used in an IASCA winning vehicle will sound really good in that car. Take the same equipment and put it in a different car and it sounds completely different. Why? The inside of every car is different, listening positions are different, material is different (leather, cloth, etc), speaker placement is different, you get the point.
I'd recommend you listen to some speakers at your local stereo shop to make a more informed decision. I'd hate for you to spend tons of money on equipment only to be disappointed. If you are having a local stereo shop do the install, then maybe they can audition the different brands they carry in your car to see which sounds better to you once installed.
There are still many other brands out there so be sure to do some reading