[cochino12]

my $.02 is to use one or two 10" subs. The human ear can only hear down to about 20hz anyway. So if you get 5-10hz lower with a 12" sub it's not going to be audible. I don't think you'll feel much of a diffrence either since it will be in a truck. A 10" sub can play well below 30hz while using less space than a 12" sub. Spend the $$ on the amp and you can get by with an average sub.