You'll need to get in touch with the Hot Bits distributor for info regarding OE replacement applications, everything I've heard about them (and you can read in the above links) is from the racing applications. The fact they make a decent racing product though is usually a pretty good endorsement.

As for the 7100 Bilstein, it is not a direct replacement and I'm working on an install kit you would need to take to a machine or fab shop to replace the stock front shock mounts. The 7100 itself is a motorsports shock that's rebuildable, custom valveable and available in coil-over. So you dictate everything about how it's going to suit your application when you select valving, plus the added flexibility if you go coil-over. Definitely not a "plug-n-play" proposition, but one I feel suits the VX better and offers the best long-term value in suspension. Once installed all you would ever do is rebuild as needed and, if using coil-overs, change or adjust the springs to suit your needs.