umm i had a set of polk momos a few months back. it got the job done. relatively loud and put out pretty good SQ. i say if you can get them cheap go for it.
i did do an a/b comparison with the 10" polk momo sub with an 10" idq. the polk got louder but it didn't even come close to the IDQ in regards to SQ. the polk had more of a boomy sound while the idq was super clean and tight.