So lemme make sure I have this straight. Two 5x7's will fit w/o modification. 1 6x9 would fit (in the center hole) w/o modification.

 

That is correct. You even have 2 round holes on the outside of the package tray metal for some small round speakers. If you want 2 6 X 9's, you have to mount them from underneath the 5 X 7 holes.
It takes about a nano second to take your package tray out, so do that and you will see what I am talking about.

 

Package tray is out. I see what you mean. I think I'm going to go w/ 2 5x7's.

 

There is nothing in my interior at all...the package tray is out. I see what you mean. I think I'm going to go w/ 2 5x7's.

 

Not sure how the bass response will be with the smaller speakers though.

 

True, maybe slick can comment on that. No matter what size though you get what you pay for...If I pay enough I'll get good bass response, Crutchfield probably has some decent 5x7's.