as far as i know yes its the head of the engine thats different, everything else is the same...
obviously they will sound different but my 8v daily hack sounds anything but harsh
as for the clutch mech, cant comment on this i think they were different at certain years, sure someone will know...but come on that is just clutching at staws, my 8v has a different engine code to some other 8vs, means naff all...
but yeah the rest of the car is supposed to be more or less the same, even says so in the original GTI catalogue i have in my hand right now...
P.s...i wasnt on about performance figures, the only reason i posted on this waste of time thread was because i just thought a few things needed pointing out
everyone with half of brain knows a 16v is alot faster than the 8v, they will feel different to drive for sure, but in reality not than many things are different between the two...