It's not really about how you mount it. It's more about how big you build your box. I have mine straight up in the middle. No more trunk space, but my 12s sound mighty nice. My friend went and got one 10 and put it in the front left corner of the trunk. Built a custom box for to fit in that corner and everything. If you want, I might be able to get another one of those boxes made and get you a price, but it'd only be for one 10. Let me know because I have a friend who knows how to design good boxes.