In 30 years of messing with watches, I have never done a trade, always buy and sell. That all might change, as a good friend and fellow watch collector has a vintage Girard Perregaux two register chrono with the 38mm case and Excelsior Park movement. Is is in great original condition and runs well. I have a 16030 DJ with boxes, papers, booklets and hangtags. It is has never been polished, and shows, and will most likely need a service soon. I am trying to find a value range for the GP since it is outside of my wheelhouse, so any input would be greatly appreciated.