2 jl w6 vs w7 and 12 vs 13

How can you have that opinion if your only experience is with an improperly set up W7?  Linear motor topology woofers like the W7 are in a leage of their own IMO.  But then based on your posts I'd say you are looking more for output than SQ so I would say you made the correct decision.  I hope you enjoy your new system!

800 watts would work just fine with the W7.  I am in the process of building a system using a single 12W7 and a 500/1.  What's nice is the lower power allows me to build the enclosure a little larger without worrying about the customer damaging the sub. 

I wouldn't recommend running the amp below it's rated impedance.  It will more than likely eventually damage the amplifier, and the damage may not stop at just the amp.  Keep in mind that power ratings are only helpful as guides, not as audio laws.  As long as you are happy with the results, don't worry about the fact that you aren't loading the amplifier to it's limits.  Because to be honest, the difference in output produced from a sub running at 800 watts compared to 1600 watts is only 3dB which isn't that noticeable.  And that's without taking into account power and thermal compression from the sub and power supply sag in the amp.

No No!

Dude - if you want OUTPUT you want CONE AREA.

No!  None of that overbuilt, roided-out sub makes NOISE except the CONE.  All that 10 or 11 inches of subwoofer isn't going to do anything for ya except make ur install difficult.  Great, clean sound at excursion is all fine and good - but this is going into a vehicle - that chugs down the road and accepts all sorts of foriegn noise and such - the real differences between these subs (w6 and w7) are minimal at best - forget hearing a difference once this thing is installed into a vehicle meant for public roads. 

I - uhh - would seriously graph these types of statements in WinISD before you take such un-empirical observations to heart and wallet - you'll find the w7 will lag *significantly* behind the w6's under the power conditions you've laid out.

Furthermore -

I can assure you - I was dumb enough once to replace a pair of Perfects with a 13w6 - you're not going to get much out of this very expensive equipment swap.  If you want to gain SQ - I would start with deadening the entire car - not replacing such quality woofers like a DVC Perfect.

Again - go back to WinISD - you're sacrificing all kinds of output.

If you want OUTPUT, particularly anything that can compete with 12.1D's - this is a BAD idea.  Build a PORTED box to .5cft larger than the JL recommendations - especially at a paltry 800 watts.

Anyway -

If I HAD to buy subs in ur situation- I think Kephart's own perennial favorite would be highly appropriate here:

http://www.diycable.com/main/product_info.php?cPath=24_93&products_id=653

I'm assuming you went with the W7 then?  I'm glad to hear that you are happy with your system now. 

1.  Keep in mind that this is a very low distortion driver.  Non-mechanical speaker based distortion is harmonic in nature so you were probably used to your old speakers producing harmonics of the fundamental frequency that increase with excursion and volume.    So it's not missing notes, it's just not adding it's own notes.

2.  Speakers don't clip.  What you were probably hearing is either your head unit or amplifier clipping.  It can sound very mechanical.  Either that or you are hearing the sub run beyond it's mechanical limits.  Mechanical power handling is a function of the enclosure.  Either way you are pushing your system to it's limits at that point which means you should imediately turn it down before damage occurs.