its 6.75in in the front but you'll probably want to build a spacer to get a little more depth. 6x9 in the rear and no they aren't easy to get to. Email me if you need help.
I did a system install on a 98/99 galant (just front stage, hu and amp) and that was one of the easiest installs i've ever done. Even drilling in the firewall was pretty easy (nice big gap on the left side of steering crankshaft).
its 6.75in in the front but you'll probably want to build a spacer to get a little more depth. 6x9 in the rear and no they aren't easy to get to. Email me if you need help.