between a l port and a straight? not suppost to be no because they figure the "curve" into the volume. alot of people run larger ports to reduce noise other than that they are tuned to refference
If you want more SPL, then tune towards the higher end of the spectrum. I don't know what will work best for that sub off hand....but SQL is likely somewhere in the 32-35hz range, and more SPL geared tuning somewhere in the 35-40hz range. Honestly, for daily, I don't think I'd tune much higher than 40