If by "back deck" you are referring to adding holes in the rear deck of your car to let more bass from the trunk into the cab, then generally yes. Removing rear spkrs or adding holes that do not compromise the structural integrity of your car can let more bass into your listening area.
If by "back deck" you are referring to the back of the sub enclosure, then typically no. Subs are designed to work best in specific size and types of enclosures. A sealed box has certain strengths and weaknesses. They are good for tighter response and sound quality, but do not have the bass "hit" of a ported enclosure. if you cut "aero ports" in an enclosure built to your sub's specs for a sealed enclosure, then you will ruin the enclosure. If you want to build a ported box, then you need to find out exactly what size of enclosure your sub manufacturer recommends and what size and length of a port that specific sub sounds best with.
Your subs will only sound as good as the enclosure they are in. If you have a sealed box built to your sub's specs, then don't mess with it. If you want a ported box, then I'd suggest building a completely different box.
Hope that helps. God bless you.