You can only go S3 from standard or if you already have S2, thus from S2 you buy the new Inlet, 60mm throttle body and map update, the info on this is on MT website inlet group buy offer from £949 - £1149, fitting extra.
So, add S2 £1800 and fitting to that for an idea
http://www.mountunestore.com/Product/i4-Cast-Inlet-Plenum---Group-Buy---Pre-Order