I bought new speakers for my coupe but do I HAVE to have component speakers for the front? and will Polk DB650's work in the rear panels? I was also planning on installing them myself, is there somewhere that has step-by-step instructions or can anyone give me some?

 

No, you don't have to have component speakers, but you will get better imaging if you do, just because the stock woofer location is bad for imaging higher frequencies. As for a tutorial I have not seen specifically for door speaker installs, but do a search for door panel removal, and the rest is pretty self explanitory. Both myself and milox have threads with pics that show the door panels off, so you may be able to gather something from that if nothing else. And just as with the fronts, the backs will require a baffle to mount, because of the retarded bose 3 screw mount system (Let's be cool and use 3 screws instead of 4 like everyone else).
Good luck