Before you order the Triad C7-X check out the thread on the bottlehead forum it details the mod and there is some discussion on the technical aspects http://bottlehead.com/smf/index.php/topic,6030.0.html
With a standard enclosure fitting one of the chokes in is a bit of a challenge there are a few who have fitted them recently you will have a struggle getting two of them in. Much of the impact from the changes come from the large film cap most probable due to the big reduction in esr. The choke helps by substantially reducing noise and ripple. Ripple is reduced from around 1.5m in the standard Crack to 67u with the choke fitted.
By the way my case is about a inch deeper than a standard Crack enclosure.
Again Thank You Very Much!