Thanks for the feedback everyone...
lgowin- you are correct about the grilles.
964TargaC2 - I may buy those just for the grilles. I have seen grills offered for as much as $20 each.
Michael T - I am going to get the mic too.
Chuck H. - Yeah, I thought I would have a problem with power. I may go with a powered sub like this one: Blaupunkt Blue Magic XLf 200 A
Maybe with this I can get away with no additional amp? If not, I think I can rewire to add one for the 4 other speakers... It i s 3.1 inches high and I am not sure it will fit under the passenger seat.
I welcome any other comments. I will also post photos of my project when I get it underway.