will any standard sized 6 1/2" fit? will it fit into the factory mount(with or without the plastic cage)? what about the tweeters? anything special features i should look out for to make it fit properly. thanks in advance.

 

any shall fit, as long as they are not oversize. Also the depth can't be too deep or it will hit the window. But you can make any speaker fit if you build a mounting surface for it .