As to the question of "damaging" the car with the top off:
If you reduce flow to that duct, you will NOT damage anything. At most, you could see a reduction in power output. Remember, this is the air intake for the engine, not a cooling system. And you are not restricting airflow, you are at most increasing turbulence around the intake as opposed to nice smooth flow in. It may work better with the roof on, but you will not do any harm to any engine bit. My butt dyno says there is very little power drop (if any). To quote my knowledgeable salesman/enthusiast, you would have to "measure it in laptimes". Since I'll be lapping with the roof on, it matters not.
My grommets are here, so I hope to get to it tonight.
