DIY Sub vs Big Name Subs

I have N802's and I have been thinking of integrating a sub into the system to augment the bass. They are awesome at punchy bass but not into the low regions.

Will a kit sub like VMPS or Northcreek be able to compete with say a B&W ASW 800 or REL Stadium?

I could get 2 diy subs to run in stereo for quite a bit less than a single "big name" sub.

Another problem with REL is that with monoblocks I am forced to buy 2 and I cannot afford that much.

B&W N802s
Parasound JC1 Monoblocks
Cary SLP2002

hard to beat a vmps sub-in kit form they are a even better deal-
i bought my vmps large as a kit
I hope they are better, I'm building a Northcreek Thunder right now and will let you know how it compares to my other sub in a few days. I built the Northcreek Eska towers just recently and I have been very pleased with the result: very musical, accurate, fast, and flat from about 55Hz on up. With the Thunder I hope to get a nice deep and integrated base down to 20Hz.
how did your northcreeks compare to name brand speakers/subs?