See, that's generally what I was thinking. I've seen and heard some insane builds with Fi and know them as one of the high end comp brands when I first got into this stuff. Now I'm seeing stuff saying Sundown is comparable. Which, I could see it being an awesome contender, but if I were building a daily ground pounder with one sub for 1000w or less, would it really be able to keep up with an Fi SSD (or even the new X), Lethal Injection, Ascendent Audio Chaos. I'm talking about a large (ish) box and massive port area to really let these things hit full excursion at 40+ mm peak to peak.
I feel like the soft parts would wear out over time on that kind of a beating. Don't get me wrong, I really like and want to do a build with Sundown, I just feel like you get the next step in quality and durability with the American subs.
To me, granted a relatively uneducated opinion, you have
Lethal Injection / Fi SSD (fully loaded on both with extra spiders etc..)
And AA Chaos
Then
Sundown SA rev 3 (little boost is thermal capacity) / SQ HDS3 / American Bass XFL
Everything else "budget"