a few years back, a 15" round solo was in my truck, it is in my top 5 subs I have owned all time, ran it sealed and loved it, the output was greater than my RL-p 12D2, but that is due to cone size, but with out a doubt the RL-p is a more versitale and cleaner sub to my ears in my install, and from my experience the RL-p will take big power with more ease, Mike will gladly give you all the info you want, but if you are looking at a 12", ported you should look to build in the 1.5 to 2.0 cubes range, and try to aim to tune it in the 27 - 34hz area, I choose the large box for a little more efficency and tuned low for all kinds of clarity, a few people have said no SQ was lost in tuning around 34hz and gained more output, great choice