I have the JL XR525 Csi & Cxi & I love them!
They sound really sweet highs without the kind of harshness like the MB Quarts. The JL's have really big open sound unlike some others that I have heard, like the Alpine Type Rs or Pioneer Premiers if you know what they sound like.
The XO have nice functions but kind of ugly, IMO. You can adjust diff. levels on both the Tweeters and Mids and the CSi can also be configured to run Bi Wires.
Keep in mind that they are rated RMS 65W!. Don't run too much power to them or you will burn out the tweeters (a friend of mind burned out two sets of tweeters with a MTX 250W x 2). I think you can safely run them with about 100W per side with no prob becuz thats how mind is.
Thay are sort of pricey if you buy them on retail. I bought my sets from this Ebayer for $197 (CSi) & about $160 (CXi). His Ebay id: CarAudioWarehouse. He sells these all the time.
THe VR & TR are also really nice eventhough they don't have external XO. THe only reason I got the Cxi instead of a pair of VRs is becuz the XR & VR are not made in Germany.
I hope this helps.LoL
JL Audio XR 525CSi
JL Audio XR 525 CXi
Pheonix Gold Tantrum BassCube
Pair of JL 10W6V2