Soft brake pedal

[evilC]

Are you running the same discs (rotors)? If so then the cross section shape of the disc will have been determined by the VW twin pots causing too much stand off on the new front pads in the new calipers. The only way to over come that is to increase the stroke on the m/c - hence the soft pedal feel.
For a better understanding of what you've got can you describe more fully the brake spec - disc size, caliper type and piston size, both for front and rear.