the_noise: before you buy replacement speakers for your ride, i would highly recommend that you first buy a decent head unit (sorry, I cannot ascertain your Pioneer 2850 HU as I couldn't find it in the net).

My older van used to have pathetic sound. Then, I bought a head unit with higher power output (something like 45W per channel) [and capable of playing MP3 files].

It made a lot of difference even with stock speakers. I never changed the speakers after that and I am very satisfied with my setup, with my style of music, i.e. something to keep me awake while I am driving....

My 2 cents.