...and a standard S3 is?
Basically nothing is standard.
16v with Cams, head, lightweight lifters / titanium retainers, big TB, re-map to give 190+ BHP, lower FD, C/R gearbox, Quaife diff, Koni coilovers, Eibach ARBs, poly bushes, aggressive alignment, S3 front brakes, braided hoses and track pads.
Lighter weight + better handling + stronger brakes + lower gearing + less understeer/more front end grip = quicker. Simple.
...and the Mk5 GTI has a far better chassis, with more power and torque.
Fair enough ESS. I thought you were comparing a standard S3 to a standard MK3 GTI. I do agree with you, a MK5 GTI does have a great chassis showing big bhp (VXR 240bhp) means nothing unless you can use it.