Hi again,

Another link here for the X-force systems with pics.
X-force Varex system is $1350.
Normal X-force system si $1250.
Varex is noise adjustable while the other is the same except for the noise adjustment.
http://www.perth-wrx.com/vb/evolution-r/46823-x-force-varex-muffler-exhaust-systems-4.html

Cheers,
Mao/Evolution R