Don;t get me started on exhausts!
I spent months looking for a half decent pipe set for my 750F2, and got so sick of looking at rotted out, scabby lumps of metal with huge holes blown in the silencers being sold for £200+
Pipes so clearly rusted through and rotted out they would never be usable, yet sold for the sort of money you would expect to pay for a new system on a modern bike. Old rare parts they may be....but most of what I saw was unusable.