I'm reminded of a situation we've seen more than once.

The E36 BMW Coupes are known as the race cars w/the famous collapsible roof. I am not sure why they were designed that way, but for a performance car the roof of the coupe version is not well supported at all.

Turn 3 at Summit Point is a world famous "car catcher" if the driver makes a mistake and then tries to correct instead of going safely off. If he goes off sideways instead of straight, the starboard wheels will catch a drop over the gater and the car starts rolling.

There was a famous case there of an E36 BMW M3 coupe that went off there and rolled several times, to the point that the roof had collapsed all the way down to the beltline.

It was impossible to get into the car, and the instructor and driver had to be cut out.

However, they were in a car with street equipment only.

The seatbacks broke, and as the roof collapsed they were pushed over onto each other. Perhaps they didn't necessarily want to end up with their heads in each other's laps, but they both were able to walk away from the wreck because the OEM safety equipment worked as it was supposed to.

When you make a change to a car's safety equipment, the entire system has to be reconsidered, and it's a bad idea to install items in piecemeal fashion.

My advice with normal Honda street cars is to get the rollover protection first, pad it very well. Then get the harnesses when you can (but don't drive on the street with them).

The fixed back seats should not be considered until you have the other items instealled, and remember that in some states you are required to drive with the OEM belts even though you have fixed back seats, and the OEM belts must therefore work well w/the fixed back seats. (The reason for this is that some jurisdictions do not believe you will be able to see into your blind spots if the harnesses keep you from looking over your shoulders.)

EDIT: We would not allow a car onto the track at a NASA Virginia event if it had fixed back seats w/out rollover protection.