The car I have is a 2007 Impreza and it doesn't have much room in the doors for speakers. I have heard that depth of 2.3, not exceeding 2.5 in should be fine- well 2.5 with mods and difficulty- which I don't want to mess with the doors if I don't have to. I'm trying to go with more shallow if I can.

I am having trouble finding a shallow speaker that also has really good tweeters.
I was thinking about either buying the parts separately or buying something rather cheap like the Polk Audio db6500 (can be had for about $110 on the net) and then buying some higher end silk tweeters like the CDT ES01 from cdt separately.

Is it possible to wire these and use the crossover with the Polk's?

I previously used in a diff car and liked the smoothness of the tweeters with the cdt cl61 components, but want a little more midbass and the tweeters to have some more power if possible, but still smooth.

Any other suggestions? I currently plan to keep the whole cost around $400 internet.
Yes I'm a noob, but I hope to learn much by installing this system myself, but don't want to go into it without consulting people that have the know how in this sort of thing. Thanks!!