Is it possible to place a 6.5 sub in the rear panels of a 91 GT vert? I don't wont a sub in the truck and I would like to keep it stock looking. I'm also not looking for anything crazy. Just more bass that I like.

I was thinking something like...
Kicker CompVT 10CVT651 6.5” 300W 1 Ohm
http://www.audiosavings.com/products.../10CVT651.aspx

Kicker PX200.1 (12PX200.1)
http://www.crutchfield.com/p_206PX2K...8108225&awdv=c

Would that sub be to heavy for the speaker grille?

I know that 6x8s are not for bass, but is their any recommendations for a speaker for more bass?

Maybe....
Infinity Kappa 682.11cf
http://www.crutchfield.com/p_1086821...5#overview-tab
JL Audio C5-570cw
http://www.crutchfield.com/p_136C557...cw.html?tp=111

Thanks for any advice. I just bought the 1991 triple black convertible with a stick last Monday.

 

it's possible, but it won't work worth a damn. a woofer/subwoofer needs to be properly enclosed or baffled, and the rear speaker mounts in that car can't do that.

 

Are you referring to the deck speakers? Are the vert speakers mounted the same as the coupe?
If they are mounted in the plastic side panels near the back seat, can you post a pic with the plastic panel removed to see how much space is behind it?