I jumped on the GIVI saddle bags for the GS and the RS. I believe they were about $1K for a set. The Corbins were much nicer looking, but at $1,500 a pair, even I said no way.
Pre-RT, I got fairing, and rear trunk from Corbin. That was about another $3K per bike. When done, I had a nice RT, a couple years before they came out--but I finally got smart. I have been pretty conservative with the three RT's after that. I made better money in those days--so the spending was a bit easier.