I have a Powerfield 15, I believe of the same vintage (mid 90's). Right now I have it cramped into a small space. Once we (my wife and I) get moved into a home I may look at getting a SMS or a new sub. Over the years I have wanted to upgrade to a newer sub and many people have pointed out that those Powerfield subs are quite the boomers.

I was ready to pull the trigger on a SMS because the bass was real overbearing in my room during movies (and music). Sometimes it felt like it was drowning out the movie. When I uppgraded my processor (to an outlaw 970) I was able to move the crossover frequency down to a lower level. That really did the trick for me. Now my main speakers handle down to 60Hz and the sub takes over from there. I must have had a peak between 60Hz and 80Hz. After installing the new processor I didn't feel the need to go get the SMS-1.

I am sure that only getting the SMS-1 would have also fixed my issue, but in my case I wanted the newer processor first.

Good Luck.

Charlie