I would think that the w6v2 would have better SQ than the RE SE. The w6v2 would cost more though. The w6v2 goes for bout $250 on ebay and the RE SE is <$200 straight from RE. Both are good subs.
One thing about JL subs is that they kind of have a sound that is all their own, if you know what i mean. But subs w/ XBL^2 technology have better SQ than the w6v2 IMO (brahma, koda, x.x.x., acendant audio avalanche). The AA avalanche 15" is $300 brand new. The XBL^2 subs are a step above the SE and the w6v2, both in SQ and SPL...maybe excluding the koda, i'm not sure of its SPL abilities.
What size sub are you looking for? How much power do you want to go with? And how much are you looking to spend?
If you are looking for really good SQ and some bump to, I would suggest one of the drivers that have XBL^2. I ran a brahma 10" for awhile and it really surprized me, both in SQ and SPL. That lil fella can really move some air.
I have heard some really good things about the AA Avalanche. I think someone on this board has one...I just cant remember who.
Since you say that $ is not really an issue...what about space, how much room do you have to work with? I'm not totally sure, but I think the Avalanche likes a larger box.
For 600wrms daily, your best bet may be something like an AA Avalanche or pair of Atlas subs, the w6v2...or maybe a Brahma.
Are you looking at getting a Powered4Sound snail-shell? You're gonna give an arm and a leg if you buy a P4S SS. Or do you have that copy of the "FakeShell" that is floating around?
The Avalanche should do nicly w/ 600wrms, especially if you use an well built ported box (or a snail shell).
A brahma may like to have a lil more power, but it would sound nice on 600wrms. I ran my brahma 10" on a bp600.1 for bout a month before i put it on a bp1200.1. I was doing mid 130's w/ it on the 600.1. By the way, my brahma 10" is for sell...it is being reconed right now.
The SX is a lil more SPL oriented sub, but it makes a nice daily driver. Its SQ isnt quite up to par w/ the Brahma. I run my SX15 on a bp1200.1 and it sounds pretty darn good. In the first box i built for my SX15, it did 145.1db on my first 3 burps...and its nowhere near broke in. And SX12 w/ 600wrms be pretty loud.
But w/ 600wrms, I would deffinitly look into an Avalanche.
Oh...buy the way, do you have to amp you are going to use already?
Oh...and by me saying that the SX is more SPL oriented, it doesnt mean that the sub sounds bad. Actually, the SX can sound really good in the right install.
I am going to be running my SX15 as a daily sub in my truck.
The SX12 should do pretty well on 600wrms...it can take quit a bit more though. Whatever you do, done clip the amp. I think the SX12 is bout $260 shipped from RE.
If you really want "the best", you may wanna look into going w/ more power (1200w+) and something like and RE X.X.X. 12".
You can really make 600w go farther than you would think. Having a good system doesnt entirely depend on your equipment. Its 20% equipment and 80% install. A bad install can make even the best subs sound like crap.
Clipping is when an amps is forced into trying to produce more "clean" power than it can...when it does this, it sends DC current instead of AC current to your subs. Thus it turns the speakers voice-coil into a heating-coil and will burn the sub and/or the amp up.
To avoid clipping an amp, dont turn to gains on the amp up to high. Turn it up to a point just to where the sub starts the distort, then turn is down a lil bit.
If you are looking to keep the stock alt, 600wrms is about as high as I would go. It would be a toss-up between the SX, SE, and the w6v2. The w6v2 would prolly have to best SQ and the SX may be a lil louder.
I have 2 12" RE SE's and I'm telling you I would choose them any day over the w6v2 because they have more output and SQ is beautiful will all music. They get super loud and sound good doing it. In real world applications, "street beating" they work perfect for me.
I also liked saving the money, as high as gas is I can hardly afford to ride and enjoy my music!
two RE SE 12's off of an Orion 1200D they probally get at least 650rms a piece at 1ohm and they wang. I would like to give them a clean 1000rms a peice for burps. I bet they would get soooo loud. Everyone has told me RE underrates their subs.