Once again, it all comes back to money. I can have headers made at any time for the II, but they will easily cost 4-500 bucks. This is a low volume niche of cars and unless you are making 10,000 sets, you aren't going to get a cheap priced header. If people don't want to pay the $400 for the Hookers, then they aren't going to pay $400 for the ones I can have made.
BTW, in the world of headers, you get what you pay for. A set of $120 headers is going to have thin 18 or 20 gauge steel, thin flanges, and poor fit. A good quality header with proper materials and fit will cost you a LOT more. Most of the headers I install nowadays are $600-$900 a set. And these are mass produced off the shelf, not custom made. But the fit and materials are far superior, and the vehicle owners never have to worry about leaks, or them rotting off the car.