Ignore Rhyso, the remap aint an issue as they are fine in standard form...just not blisteringly quick. I've had both manual and now DSG and I love the DSG, but do miss the involvement with the manual. DSG when remapped can be the weak point...it too can be remapped though. Quick search on here will tell you more, also check out the mkvgolfgti.co.uk forum for more indepth bits. Remaps vary in feel and power as well, so do some research into what you want if the car hasnt already been done.
I know feck all about the ST butmy Golf feels like an all round car...i.e. it can soak up the road whether pushed or pootling. Some cars just want to be thrashed everywhere, and thats what the ST reminds me of...quite lairy, but has its place. Horses for courses