Ill throw my two cents in here, as worthless as it may be...
I parallel the IDI with the turbo 2.3 ford, and with both being powerplants that cater to the people with a bit different taste, and lighter wallets, Id say you really have a narrow customer base. I tried offering a product to the 2.3 crowd that was a great product as a very decent price (for what it was), and it was very popular as far as how great it was, but when it came down to dropping cash, it just simply became not worth the trouble. It took me months to sell 4 of the items, and those were just the prototypes at a discounted price. The IDI is the same deal, only a few people actually drop cash on it to really get some performance out of it. Now Maybe it will be different for you, as you have proven that it works, but I dont see a huge customer base... The only thing I say is make sure its worth your while, and that will keep you going...