i have an alpine head unit (think 4 channel) that i'm putting in outta my beemer (pushes 6spkrs in the bmw fine w/o amp), i need suggestion for speakers.

right now i have some crappy round blown ones next to the back seats in the panels and the stock dash ones.

should i run 4 or 6 speakers?

if 4, what kind to get? put the front pair in the doors or get ones that fit in the oem dash mounts? what should i get for the rear?

if 6, what are your suggestions on location and type?

do i need to run an amp?

i might run a self powered basslink sub in the rear too.

thanks