Enclosure Response Curve

you cant compare two woofers in winisd. The program only shows you woofer performance relative to enclosure chosen.

LOL. You can certainly compare woofers in WinISD or any other accurate modeling program. You can model two or twenty different subs in the same enclosure or you can find out what each sub needs in order to find out which one meets your particular criteria... whether that be focused on performance only, size only, alignment only or of course, any combination thereof.

As for the low end response of the two above models.. there isn't a minute's difference between them. They're both flat at ~28Hz and they both go -3dB at about 26Hz. In the end, both of those subs will do about the same with respect to low end response.

Personally, I don't like the peak of the OA box but some people like peaky bass and some people don't. A lot of people (because of the conventional wisdom that 38Hz is a good tuning frequency) don't think low bass sounds good. Or, the don't know what low bass actually sounds like because their subs unload in the high tuned boxes they use.

In the end, if you're more interested in pure SPL without respect to sound quality, then a peaky box is what you'd want. However, if you want more even response from your sub, then a flat curve is more desirable. And while it is true that cabin gain will change the curve somewhat, it will not change it entirely... so modeling does give one a good idea of what things will sound like in practical use.

I think the white line would be a flatter response. Red line wants to be tuned higher for SPL.

oa curve will sound better on modern Metal/EDM/Pop/Rock music but will probably make lots of rattles because of the peak. Most of the times SQ oriented boxes will sound tight smooth but often lack higher hertz double bass pedal thump that makes you feel alive. But really it depends on a person's taste. I can appreciate an SQ oriented setup with great low end extension with nice response throughout the spectrum. However, i can also enjoy a chest pounding and midbass heavy setup as well.