that's what vw calls for. the 1.8t has forged pistons that have a relatively wide clearance and a poor rod/stroke ratio, the 5w-40 does make for a quieter engine because of those factors. you won't hurt it with a good 5w-30. between my 3 vw's i've got close to 400k miles, iv'e used total, fuchs, valvoline and mobile 502 oils in 0w/5w-40 and fuchs in 5w-30, don't see any change in consumption, cold start or gas mileage between them. use what works for you.