what does the brushes on the side pillar do? droping a hardtop without the brushes.

 

I think they just keep large debris from getting into the pillar area when the stock convertible is down, as you can get stuff down there. For some reason I had one missing on my car when I bought it, I put them back in to help protect things a bit better. You can get leaves in there and such and the top gears are down there for raising and lowering.

For a hardtop situation I don't see them helping much, unless you drive without the hard top in the open position , then they might be helpful.