I think I read that the factory ballast in early models is pretty finicky about which bulbs you use but that this was fixed in the later models. If that is true, you may be able to find some salvaged late-model ballasts for a reasonable price.
I've found that using one of the major search engines and adding "site:the370z.com" to the search string will yield better results than using the site's search feature. Eg, "
ballast site:the370z.com"