Nice link, I just sent them an email.
I found another product from GMG Motorsports group:
It's the Rear Dog Bone Kit (GMG 996 Link Kit (w/o rubber boots)): $1049 for all 4-links:
--GMG 996 Link Kit (w/o rubber boots)
http://www.gmgracing.com/porsche_suspension.shtml
for $1500 bucks I can buy 3 more sets of tires. too much money for the links. And actually, the cost breaks down like this:
$1049 parts
At Least $500 labor for install and alignment