which older models are you looking at vs. which new models?
I was looking at the older mirage subs that were $500 back in 2002 which can be had for about $100 bux now vs the HSU subs for $500 now. Thing is these HSU subs might be good at $500 in 2007 but in 2012 they would be worth what? $100?
Unless you are looking at the Mirage Substrata/Energy Microstar series, don't bother. The older Mirage "high-end" subs, while decent for the time, simply do not compare to the low end subs from todays to brands.
It "might" have the output of something like the VTF-3 MkII without the turbo, and obviously the low-end roll-off would be different. If you want a solid sub for music, I would get the Energy (if the price is right). If you want a sub for movies/music I would get one of the new Hsu subs. They are of course larger, but their performance will be better than the 10 year old Energy sub.