I remember seeing these a while back on E-Bay and was wondering what the advantages / disadvantages of them are?

Yes, they would help prevent stuff from getting into the frame rails where they are placed, but they would also prevent water and road grime from getting out, correct?


Pics are from sirshan's gallery:

 

I did see some inof on these in other posts when I ran a search. Sounds like they are mostly a cosmetic item.

Can anyone that has them clarify if they hold in water, etc.... or is it not an issue?

 

I got a set because I hated looking at the holes there. So purely cosmetic for me. Not sure if they hold water or sludge in behind them, never took them off. There are so many other holes in the frame rails that plugging four up wasn't any concern to me.

 

Would you be willing to take one off just to see if anything has built up behind there?