aftermarket speakers and autodim mirror (noob q's)

[modestmatt]

So I've read a lot of threads and done some searching, but I wanted to know what I'll need for replacing the front oem speakers.. I'm assuming I'll need a "component" set up w/ speakers and separate tweets? What size are the front door speakers? Is the hu automatically programmed for the crossovers?

I'm also thinking about upgrading to a autodim mirror w/ homelink. There are a bunch of ones on ebay, I guess I was wondering if I could just get one of those instead of the pricey subie one.

thanks all