Nice F&F but that's about all to see here, if you want a really nice Performer. There are plenty of 85 performer's about so don't rush into buy would be my thoughts. I would expect a sweet 85 F&F to fetch between £250-£300. An 84 add £100, as they seem to be a fair bit rarer (for Performers that is)
At the end of the day, these were a massive success for GT, so there are plenty about
By the way early 85 Performers that are still US made, have slightly different rear drop outs, and the 84's only have 3 holes in the rear drop outs, and no cable guide on the forks
I've got an 85 US made and an 84, that I might consider selling this year