2 18" Sub box?

[tv559 0]

I am about to install 2 18's in the back of a Gmc Sierra Ext. Cab. I will be taking the back seat out. My question is should I have the subs and port facing up or Subs facing forward and port up. I was told to have the subs facing forward and port up but I would like more opinions on this.

Thanks,

[johnecon2001 82]

Two 18's in the extended cab? With port? I'd say you're looking at almost wall size. Face both forward.