[ianacole]

When you say "track seat" are you referring to just track days, or racing with a sanctioning body, as the answer will differ based on that. For track days, unless the entity you are running with has specific rules in place, any seat you choose to run, as long as it is securely mounted (if they have a tech inspection, this will come into play), you should be good.

For racing, which may include TT, there are more stringent rules, and vary by sanctioning body. My experience is that most will allow "expired" seats with additional mounting modifications. But, I would go through the rules of any sanctioning body you plan on running with and pick the most restrictive rules to abide by.

Ultimately, the answer to your certification question is: it depends. It depends on the organization you are running with and what activity you are doing with them.

Personally, I would only buy an ebay seat that's from a manufacturer that is known and reputable ... Corbeau, Momo, Recaro, etc. Having been in a few track accidents, one that resulted in a broken back, safety is one area that I will spend extra on. I don't have a personal preference in a hinged seat versus a full bucket, for non-racing (and I include TT in racing) application - I've used Corbeaus for autocross and track days and would do so again. But, I feel there is less risk in those activities than full racing.