SEAT might have cut costs by deleting the soundproofing from the top of the engine. If there's a big black thing over the top of the engine, about 2-inches long by 1-inch wide, they haven't. If there's just engine, they have. So the first thing to do is buy the engine sound deadening kit. Next, if road noise is coming from the wheels, then it may be the tyres. The bigger the wheels, the lower the profile of the tyres and the more worn the tyres are, the worse this will be. The best tyres for an MPV are Toyo J48 205/55 R16s. I had them on a Mazda 5 for a year and they were brilliant (but then, so was the rest of the car. Far better than any other MPV for ride comfort, silence and handling).