Road racing (including instruction classes) and autocross require a helmet.
Whatever you do make sure the seat is secure with real bolts, not some of the get-by stuff people come up with like wood screws.
Maybe you can use the rails from a racing seat like Bride and interchange them with your stock seat rails? Not sure on this someone may be able to tell me if this idea would work or not.
And yes Sebring is a blast. I want to get back out there one day soon.
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if you can only race me in a straight line then whats the point 
...91 SMF SCCA
http://www.flickr.com/photos/8341770@N07/5601083432/http://www.flickr.com/photos/8341770@N07/5601083432/ by http://www.flickr.com/people/8341770@N07/, on Flickr
I see people out there spending money on the car to improve it … If you spend half that effort just working on your driving skills, making you and the car work together as a team, then you’ll go faster – period. To make the car go a second faster on the track takes a lot more energy and money than making yourself drive it one second faster.
– the late Tom Thrash SCCA Solo E Production