To a 'limey' paying more than $8 USGal for diesel here in the UK your kit sounds very interesting, but what does CNG stand for? Is it something Natural Gas? Our domestic gas is natural, and if I could use that to supplement the running costs of my '99 Mk4 Golf Tdi it'd be very useful. My car has over 115 thousand miles and still averages between 50 and 58mpg.
All the best,