use a REAL synthetic group IV oil. turbo's need top quality oil to prevent breakdown, in the USA i use Amsoil signature series oils in everything. IMO an 0W oil is not needed unless you get VERY cold weather, i used 10-30 in my modified to almost 300 hp 1.8T jetta-bora for almost 200,000 miles before trading in. a group IV 10-30 uses little to NO weak viscosity index improvers. if its very cold there amsoil's 5-30 signature series has a pour point of -60 F that should suffice. i believe on your side of the pond group III dino oils cannot be labeled synthetic as in the USA, thank castrol-BP for that!!