[warpdrive]

I just noticed that you're in Canada. The one thing you should know is that the F113 or DD15 is completely overpriced in Canada. I think the list price of the F113 is something like $4999 CAD, and the DD15 is $4k or something. I think some people in Canada got the F113 for a good deal early on, but now since most dealers think the F113 is hot stuff, you are not likely to get anywhere near your $2500 budget.

I'd highly suggest you drive down to the US and find a dealer and you could save a lot of money. If you were in the US, you could pick up the F113 from an authorized dealer for around $3K USD.

If you are not willing to do that, then the SB12 is going to be your best choice. You could always buy an SMS1 which will give you the exact same EQ (but in a separate unit) as what's inside the DD series and you get the best of both worlds.

My SB12 does pretty well in my smallish room. Due to room gain, I get extension almost down to 20Hz which is superb for a small sub (note, this graph is my unadjusted frequency response, and you can see that it's pretty flat in the low-mid bass region)