98 monte, got subs in the trunk. brother gave me a tube sub he wasnt using. where could be a good place to put the tube for het best bass.

 

I've yet to do an install in a Monte, so I can't really say. But what I can say is that you should experiment with placement to see what sounds best to you. I think you'll find that if you place it parallel to the back seat and butted up against it, it'll sound the best there. But again, try different placements to see which one you like the best.