CBR954RR

You can size the port for cone area, maximum excursion, and tuning frequency. This will ensure your port is large enough if you add more power later. In other words, if you reduce your port size based on power level, you always run the risk of not having enough port area if you decide to add more power later. Just size it for the maximum case to start with, unless you are really tight on space and it is just not possible. The mayhem 18 works great with 80-100 sqin of port.

x2

You can order a recone with or without it. The longer coil adds Xmax and is great for daily/music. In many applications, the short coil is better for SPL burps.