Yeah dude they can you might have to retro-fit them for a nice clean look, fiberglassing is something that I have seen done over the years to make it look really clean. If you plan on putting them in the front you can put them either in the door or really wherever you want them, its really up to you on this one, but it may require some cutting and such from your end.

You don't necessarily have to get a crossover cause the tweeters only hit a certain range of frequency anyway, so crossovers are not necessary. That is just if you have the subs in the doors that come with the component systems.