Jl fathom f212 diy vs JL's version

Looking at redoing my subs on my stereo which is presently a pair of mirage subs of some model.... They are my wife's and each have a single 8in driver. They sound very boomy.... Cannot play deep and well... I don't like them :). Presently I only use the sub for ht due to not liking how they sound. Ideally I would like to use the subs all the time.....

So I want to get something different. Went to a local car audio shop where I know the owner (talked to him about my car setup) and he said he would sell me a new fathom f113 for $2,500. I know I would need two of them but it would be a while before I could afford a second one.....

Or.... Make one myself which is what the owner of the shop said he would do. I thought I could use a 2 pairs of the jl audio 12w6 subs vs the w7's they use in their home theatre sub line. I would have around $1,600 in four 12 in subs so going this route it would be more like a f212...... And I thought I would use wyred 4 sounds sx1000 to power them, or possibly the mono block version.

Is the room correction stuff worth that much added cost? I have a integra 80.1 pre/pro, old infinity kappa 8.1, 5.1 and kappa video speakers presently powered by parasound hca1500 amps.