Yeah I thought about keeping the 15 for the lows too, but it's really just a space issue. And MTT I'm not really sure what IB means. I guess I'm still a bit of a noob. But this is the way I think of it... the reason for low bass is the amount of air pushed, so that means the surface area of the cones...so the surface area of 3 8" subs would be similar to a 12" would it not? Correct me if I'm wrong by all means it just seems to make sense lol. It just seems ideal because it would be able to get some nice drum kicks for metal and also handle decently (although not as well as the 15) some of the lower ranges.. also it just doesn't seem like I'd be doing this sub justice by putting it in a sealed box. I'm really having a hard time deciding because I have mixed feelings about this sub..it's great for the lows and would be really loud (for my standards anyway) but it lacks the punch of smaller subs. This isn't my only option though, I'm open to suggestions.

Oh and take note that my friend offered me 600 for my sub in the box lol.

A subwoofers diameter does not necessaraly play a role in how low it can produce frequencies. It's more about it output ability. The 8w7 plays low and loud. But it's still not in the same league as a JBL 15GTi (which is the best allround 15" in production today, IMHO). Just not a fair comparison. If you want to save space, stick the GTi in 1.5ft3 sealed (plus displacement) and you should be very happy. It will still play low and loud. The 8w7 needs a big box, so 3 of them will not save you any real space. The Gti is also more effeicent then the 8w7, which helps to.

ok you're probably right. I seem to be getting alot of people telling me to keep it. Would I get some better kicks if i just got some nice mid range speakers? I listen to a wide variety of music so I guess I'm just trying to get the best of both worlds. Will this sub in a sealed box still be loud when it's way back in the trunk? the seats don't fold down..

Loud is a relitive term. I think it will be loud, yes. Having a good midbass driver may be a better option for you. There are lots to choose from.

I listen to metal as well, the chest caving kick you're looking for doesn't come from a sub, part of the note will, but the attack of it comes from the midbass, get yourself some kickass midbass and I think you'll find the sound you're looking for...and save some money in the meantime.
You dont have to go crazy expensive, but Dima (also of Team Fozzz) is running some lotus 8's for midbass duty and they cover the kick-drum VERY well.

^^what he said...that GTi is a fantastic sub, and in a sealed box of that size, powered with that amp you have, it will provide more than enough deep low bass and output for a daily driver and sound amazing. That's the driver I was going to use, but it would have required more work to integrate than I was willing to put in, hence the 2 type R 12's. I still love the sound of JBL high end speakers. IMHO they're as close to concert sound in terms of tonality as I've ever heard. Kind of makes sense considering they're probably the speakers you're listening too at a concert anyway!

yeah that sounds like a good idea i suppose. never really been a fan of sealed enclosures though. But then again I've never actually heard a good sealed enclosure because I've just been fed the idea that ported means better. So what are some recommended midranges and where can I get a nice sealed box design?

Sealed is "better", ported is just "louder" but more detrimental to SQ. I ran 4-8" subs in an '86 MR2 with 250wrms to each and it hit so hard that the tops of the doors would flex away from the weatherstripping!!! "going low" with the 8's definitely wasnt an issue but blurred vision was.

In the sense that you've already got a nice 15 though... a smaller sealed enclosure is way more $$$ friendly and the box size for 3-8" sealed (approx. 0.75- 1 ft3 each) will actually give you the exact same size box as a 1.5 ft3 sealed box for the 15 you've got.

Just my $0.02

yeah i was curious about 8" subs for the exact reason you just explained. i would love to have something that hits as hard as those. although this does seem like the better idea because this way i'll have lows and all i'll have to buy are some mids...are there some suggestions for good mids? i really wanna feel the drum kicks. and also, is there a good place to get a nice design for a box?

A lot of people would disagree with that including myself.

I think that notion comes from people who can't make a good ported box.