Problem is its not cutting edge enough for someone wanting the latest head down racer, not old enough to be a classic, and its lack of mudgauard and carrier mounting points weighs against it as a fast daily tool or commuter. It would indeed be appealing for a turbo, but the sun is about to come out so its not the ideal time to find those buyers.
Felt make very nice riding bikes that punch well above their price point, but this model at that age has a rather limited potential audience, so I'd suggest £200-£250ish.
Felt don't sell well in the UK (they're a top flight brand but have never been marketed seriously over here) so its not uncommon to find last years £1000 bike languishing in stock for £500, which further impacts used values. Its great for new buyers though, and is how I got my F75.
You don't state why youre selling, but if you're selling to buy a bit for performance then its worth bearing in mind those Z series bikes really benefit from a nice et of wheels. 3 or 4 hundred quid spent on modest DT Swiss wheels for the Z would probably give you a livlier, more enjoyable ride than a newee bike on standard cheap hoops.