Well one thing is for sure, the iCAT isn't a big capacitor. With some hunting around you'll see that the iKAT uses a diode to change the spark signature which ultimately affects the flame front in the cyclinder. A capacitor stores the energy then releases it (which can and does cause sparkplug damage); the diode's actions makes all the difference without the damage.
Yup they ain't cheap but the benefits are awesome.
(ah hell, i just read page 2 and seen you guys already know this now no matter i'll leave the post anyhows)