yea, after the turbo outlet it goes straight to 63mm the whole way, apart from the entry and exit from the cooler. Mine works fantastically well!
I did have a cold side kit at the time of fitting yes, although the DV has since been moved back to the first alloy charge pipe after the turbo, Niki prefered it this way.
Wellys setup, and parts list, is his way of installing it on an S3 / LCR (silly left handed inlet), and the lower section is much more visable.
Mine works for a ko3 / ko4 setup on a mk4 golf / LC / A3 running a right handed inlet.
Only change between ko3 and ko4 fitment is the first pipe, ko3 fitment uses a silicon 51-63 straight expansion onto an alloy 90, then a coupler onto the 45 and down, ko4 fitment just uses a 51-63 90 reducer straight off the turbo.