Agreed. Name your budget, and get something people have used and can comment on. I have heard some diesel audio subs before, and they were incredibly cheap and the SQ was awful.
Well, they arent horrible. Depends on how much you found them for. They do have a 5 year warranty. The NSH sries you are talking about, has horrible SQ, but geared toward SPL. IF you found it cheap not to bad of a buy. Give link where you found it.