Shoduchi has the 420 on his and he loves it. Looking at dyno plots, the 420 isn't much slower to spool than the stock turbo, and you get a much fatter mid and top end.
The 480 is a pointless imo. For starters the stock engine cannot handle that kind of pressure and it's too far the wrong way into the lag compromise for a road car. And also, once you're past 400hp, an extra 50 or so won't be that amazing. I've been there and done it. To make a worthwhile difference to your butt dyno past 400hp, you need another 100-150hp.
Look a little deeper into your options than just a bolt-on turbo mate. Consider a MK7 Golf R engine swap. You'll get 380hp from a remap with the stock turbo and its a much stronger engine than the ED30 unit. When all is said and done, you might find the price difference isn't that great. The Siemens ECU can be made to work in a MK5 keeping all your clocks etc working as intended, so it's certainly worth consideration
Traction will always be an issue which ever route you take though. Bear in mind the stock turbo has the TC light flickering constantly over winter as it is!!