I totally agree, I always try to use such as Shell V-Power, or at least a Super fuel. If I am not sure of the quality, or I have no option but to buy the cheap stuff, I keep a bottle of Redex in the car and whack a chunk of that in, which helps. You have a Supercar, so give it the best you can as often as you can, it works. Supermarket fuels can have allsorts in them and for an ordinary car that does not matter much, but Maserati's are high breds and they need caviar...!!!