Window Regulator Clips?

I need to purchase regulator clips because all of mine have broken on passenger and driver side, i would like to buy the metal upgraded clips but can't seem to find them on the net, does anyone know where i can buy the clips? I have a 99.5 TDI Jetta.

Will this work for the 4 door models? Also is this for both sides or one?

http://www.ecstuning.com/Volkswagen-Golf_IV--TDI/Search/Window_Regulator_Clip/ES314681/

Is it worth it to pro-actively replace the plastic ones with metal ones if the plastic ones haven't broken yet? Is the window-drop syndrome something my car suffers from?

Just a word of caution regarding replacement clips. I bought a cable/clip kit at a VW dealer before I hard the door completely apart. Guess what: the "new" kit came with the old plastic clips and my door already had the metal clips due to replacement for a cable/clip failure a few years back. I'm going to re-use the clips of course and take the kit back. Buyer beware!