Having spoken to someone who knows, A standard 1.8t is 155-165bhp, hence why one persons 1.8t is quicker than another's, VW will guarantee that your car what ever it is, is a minimum of what is stated in there brochure weather it be 150bhp, 180bhp or 225bhp, however VW cannot or cant be bothered to pin point exact bhp so bhp can vary from an extra 5-15bhp, I only found out because when i got mine I put it on a rolling road befor mods and it was pushing out 159bhp so being abit confused I asked the question what is standard bhp, this is all apparent, Idont know the full facts, Its only what i've been told by someone who's in the industry, hope this is helpfull to anyone thats interested,
Oh and by the way I've had a couple of MKIII 16v golf's off the lights so I'd say the 1.8t is quicker, don't know about top end, never raced one on a motorway