I stopped reading this after the 3rd line..
I'm not sure what size sub you are looking at getting, but I think the only way for the JL to be worth the money is to push 12" or more. I had purchased the 10" wedge a few years back for my CRX, and returned it after a few days. My 6.5" Kicker hit harder and deeper, and actually clipped less. Eventually I upgraded to a 15" Eclipse - WAY to big for a CRX (louder than sh!t thought). Eventually I toned it down to an 8" Eclipse that was housed in a Kicker Comp (I think Comp) box - the one that looks like a giant shoebox.
That was the best sound system I ever had....
My friend has a 12" Phoenix Gold in his trunk with MB Quart in the doors. He drive a 2002 Mercedez and it hits HARD. It was a little to bright for me though.
That's what I like about the Infinity crossovers - they have a -3 db drop available for the tweeters - so if it's too bright, you can tweak it a bit. The downside - it's a larger tweeter hole than exists in the car now, and the mount ring looks like it might be a bit deep.