ther Mk6 GTI probably has updated suspension components so they may not be a direct swap. i'd imagine ETKA would be your friend on this. i'd imagine there shouldn't be an issue the provided you've got all the bits
aftermarket wise i've seen them advertised as Mk5/Mk6 suspension. the Mk6 is really a Mk5 facelift. there's no reason they shouldn't be interchangable.