I tried knockoffs from unknown brands on my Town Car and had problems with one that was trashed right off the bat due to poor fitment, and a second one that burnt out in less than 30 days. They've been replaced, and so far, my lights working.
This Dorman 2 pin ballast MAY fit additional cars, including maybe early Town Cars but the only thing I know for sure is they fit Navigators, 2003 to 2005. Do yourself a favor and check yours first.
PRO TIP: Be VERY CAREFUL removing the short cable that runs from bulb to ballast as it has the strangest pin connection and can be difficult to remove (from the bulb). I damaged a cable and had to replace it, so maybe you get to avoid that. When in doubt, buy a new cable as often people blame the ballast for their problem with flickering lights when it was cable damage IF you should ever have to replace the bulb, but if all you're replacing is the ballast and not the bulb, you should be just fine