Would it be ok to set this sub upright?

Question

I have a 1995 Nissan Pathfinder, and I am not quite sure if I will be able to lay my new dual MTX Jackhammer sub system flat on the floor of the trunk. I have a spare tire to the side, so I am unsure at the moment if it would be able to fit flat. If I stood it up, I am more than sure that there is enough room. The question is, is it ok to stand the subs up? Will they be able to be mounted properly?

Here is the sub:

http://www.circuitcity.com/ccd/productDetail.do?oid=192803#CustomerRatings

and here is the setup I am considering if it doesn't have enough room to lay flat:

http://img172.imageshack.us/img172/5834/51603739jp0.jpg

Answer 1

it wont hurt those subs to stack them, just make sure they are secure to the side of the trunk you dont want them bouncing around.

by the way i love jackhammers. great choice