Mustang 5.0

I've heard you should have your port on the same face of the box as your sub. If I don't will it make a large difference?

lemonlime

I'm not much of a pro when it comes to vented enclosures, but traditionally, that's always been one of the golden rules, and I'm sure there is some technical reason behind it. Many quality home theatre subs do not follow the rule and sound great, so I doubt it makes a huge difference.

Hardwrkr

iTrader: (5)

The reason being, I believe, is because of cancellation. The only problem though is that it is really difficult to judge how much cancellation you're going to get with each system setup. I've heard of people having better results facing the sub to the back and firing the port to the side rather than both in the same direction.
I think it's really hard to judge so facing them the same way is what most people have found to give the most consistent results. It's like moving the sub around in the trunk. You have to try it each way to find what works because every vehicle will give different results.