Dicky G is correct, at first glance this car does look like a Cup but on closer inspection there are a few giveaways. Although it has Cup badges on the doors there is no numbered plaque inside the car as per all LHD Cups, there is also a standard fuel filler rather than the correct Cup aluminium race style filler. The Tridents front and rear lack the red stripes, the steering wheel is a standard GT wooden one rather than a Momo wheel and there is wood trim rather than the carbon fibre effect trim normally found on a Cup (although it was possible to specify wood if preferred). The exhausts are also not correct for a Cup, this car has 4 outlets compared to the Cup's single outlet per side. The brakes are also not correct for a Cup, this car has standard calipers rather than the Brembos fitted to a Cup. I suspect the seller has got confused with BHP & KW as the power for a 2.0GT is 306BHP rather than 306KW. The seller is a well known & long established Maserati dealer called Fratelli Campana (Bell brothers).
would therefore conclude that the car is a GT with Cup badges & wheels & jolly nice it looks too