sub in the rear speaker location
 

Has anyone done a low profile sub enclosure to replace the rear speaker? It seems like a shallow mount sub would fit nicely in that locations, perhaps a 8" or maybe even a 10"?

Definitely would fit nicely with a custom enclosure. Biggest issue I think you would come across is massive rattling from the factory panel. Best plan would be to get rid of the panel all together and have a custom fiberglass box made to cover what the panel did and carpet it.

Too much weight to be worth it IMO.

Can't weigh that much more than a custom trunk enclosure though... Hmmmm. If only someone made this. I'd buy the oem+ system if it had a sub in this location.

I'm working on this. First version used an 8" and I'm not happy with it, going to modify it for a little more volume and use a 10" thin mount alpine driver.

My pics are interspersed with AtlasMick's in the following thread:

http://www.ft86club.com/forums/showthread.php?t=66561

I'm going to install the SI BM MKIV 12" subs in my rear speaker locations. The mounting depth is 3.3" and only requires .5 cu ft airspace. I'm going to do something similar to what @toast did as far as the enclosure.