I'm very surprised that most GSSF unlimited guns don't have comps or ports. I've saved tons of pics from GT, granted I don't know their intended use, but lots appeared to have comps.
I know that the Carver mount is probably the most popular, ala "Team Carver Mounts" and I've thought about his mount, but it costs more that John's and just doesn't look as cool to me. It seems functional, you don't have to drill the frame but it just not it for me.
From the sounds of the early posts I make end with a freak gun.
As I said earlier, I have a second gen 17L that I could just do the ported barrel but it's a two pin second gen frame that I don't think I want to modify. I bet that would be a cool gun though.