The parts availability is good and bad.
In terms of brakes & suspension it's very good as they have been fitted to many other VW Group cars for over 20 years and as such, the market is flooded with parts at low prices. The dashboard is the same as an A4 Convertible and there are loads of them being broken for spares on the internet so the parts can be cheap. The exterior door trims, rear doors (fronts fit but mirrors are in different places), radiator, intercoolers, air con parts and most of the interior trim are shared with the A4 so they're reasonably priced too. The engine is shared with the newer A4 and A5 so parts are readily available but not necessarily cheap! The bad news is the Exeo specific stuff like headlights, bumpers, bonnet, front wings, wheels, etc are really expensive and hard to get in the UK as it was poorly promoted and no-one bought it. Bumpers are still available, last time I asked TPS they were over £400 each and then you have to add the grilles and diffusers. These cars are rare and are only becoming rarer as they get written off in minor prangs.