When I bought my car it didnt' come with any speakers other then in the door panels.. Have any of you guys replace the wiring and speakers in your cars. Where are the best routes to run wire to make it look clean.. And what size speakers od you guys recommend ?

used: I already bought a head unit because I didn't feel like going to the dealer to get the security code for the head unit that was in there. other than it didn't have a cd play in it. I also bought some Rockford Fosgate 6.5 speakers to put in the front is that the right size...? let me know thanks