Has anyone found a good mounting depth for the door speakers?

Front 6 1/2's?

Rear 4 or 5 1/4's?

I am about to buy but don't want alot of work...I found some but depth is 2.75(6 1/2). Too much? or too much work with out rigging?

Thanks guys, you've helped me with all my ?'s.

Bryanb