Running costs for me are small because I only use it during the summer . I've only done 3000KMS since I bought it. To be honest I wouldn't like to run it as a daily driver as they do like a drop of petrol but to be fair it wasn't made for economy !!!!.
As for reliability I would say its great. Engines are strong and gearboxes are bullet proof . As with any performance car they do need to be looked after correctly . My Spec C is totally standard apart from exhaust and a remap for our crap petrol over here. I would recommend one to anybody but finding a nice clean example is getting very hard these days so importing from Japan is probably the best option.