I This one got my interest, until I saw $300 apiece... still tho, these Sunfire subs are s'posed to be pretty good subs? https://phoenix.craigslist.org/nph/ele/d/scottsdale-sunfire-true-subwoofers/7305242993.html still have my original True Subwoofer (MK I) from '97. The tech and performance at the time were groundbreaking and it is amazing what they can produce from such a small driver and cabinet compliment. That being said, they probably do not measure well by today's standards and I am sure any sub in your stable can out perform them. All that being said, $300 per is a pretty good price (I sold my MK II for $600 a couple of years ago) but I would imagine they have not had a tune-up (which they will probably need). Bill Flannery in WA (ex Sunfire tech) charges about $300 to work his magic: https://www.flannerysvintageaudio.com/