http://www.turbocity.com/VWEfiTurboMain.htm

The systems are a "bolt-on".  The exhuast flanges need to be reversed- the WBX exhaust bolt pattern is reversed from the T1 engine.

If you have AC, the end pieces that bolt to the head MIGHT need to be reversed to fit.

Otherwise, remove the stock FI and exhaust and bolt on the new FI/Turbo system.

The rear deck lid will need to be modified.

I would only do this on a new engine that is prepared to handle the power from the turbo...

counterweighted crank
Turbo Gold ceramic coatings on all parts ouches heat
Full race balancing
And other T1 performance parts.

If you just slap a turbo to an high mileage engine, it will have a shortened life.

If you do not prepare the new engine for the power increase, it will have a short life also.

RObert