Cheap solution for deep bass sub

[nac134]

I was about to throw out an IKEA coffee table, until I realized that it was made from mostly 3/4 inch MDF, and actually had a brace across the middle. A few screws, silicone, and some braces, made this an ultra low cost enclosure that was very stiff. Im using a digital crossover (Behringer DEC2496) so it wont make a peep over 40 hz. I put a pair of very well damped 12" pioneer car subs in it - I can't believe how it sounds. My mains are Innersound Isis mk.3 which are properly high end. But I have to say, mid priced pioneer subs in a tight enclosure provides suprisingly clean sub bass. Most of the time you can put your finger on the woofers, and they aren't moving - but when they do, you would never know it - it just sounds like my mains are reaching really low. As an incredible bonus - the unit actually fits under the futon on my living room.

The question I am asking - if you are only dealing with really deep bass (below 40hz) is there anything that the "hifi" driver manufacturers (vifa, dynaudio, etc) have to offer that the budget companies can't match? I've been able to play with the higest end velodyne stuff, and it always seemed that it was the midbass that was the difference between the great and the average. Im playin' this cheapo sub, and its totally transparent - soundstage is deeper and wider, but it does not sound like there is more bass. Im using a Rotel amp, around 120 wpc to power them. Opinions?