Yep, wiring and ECU work will be the biggest of all the big headaches if you've ever had in your life. Possibly even migraine inducing.
It does have some benefits though. It has variable cam lift *and* duration on both inlet and exhaust (very similar to Honda's VTEC), so improved off boost torque, more midrange grunt and more top end power. And obviously it will bolt right in.
After you've picked apart the wiring harnesses and removed the redundant wires, you then have the daunting task of getting all the systems communicating happily. You'll probably need the MK7 instrument cluster and key-less start system. And once you've established comms and the engine starts, the fun will really begin. There will be literally dozens of fault codes to pick through and figure out how to turn off. You might be lucky with some systems being a simple "On/off" byte, but chances are, the ECU is gonna whine like a bitch about everything.
And this is all assuming you can find someone who can actually hack into a MK7 ECU, because you know how clever they are right? Even tuning boxes are becoming obsolete (all they do is intercept the MAP sensor and tell the ECU it's running less boost than it really is) because of complex modelling. The ECU looks at all of the sensors and if they don't add up, it'll just shut the throttle. The days of Revo et al are fast becoming numbered. They can currently flash an ECU in a standard car obviously, but when it comes to retrofitting that ECU into an older car and dropping all of the MK7's systems.......you're gonna struggle.
So yeah......it's going to be a massive challenge.
In terms of man hours labour cost and yours and their time, it will be WAAAAAAY cheaper to bin off the MK7 ECU and go with a Syvecs or Life Racing. Haltech are offering DI support next year too.