Depends what you want, if your a VW fan then this will be a great modified car once done correctly, the car will need a lot of work to suspension, brakes, electronics, to fit this engine, however, there are specialist insurers out there (adrian flux) who will insure this car with no problems providing the work has been done correctly, You will however never recoup the investment in putting in the new engine, although the car in some circles would be worth much more with the 20vt engine. The easier route is to sell it and buy a leon 20vt or a golf mk 4 anniversary gti.
I have done this a couple of times in the past with golfs and corrados, and it was fun, however i wouldn't do it now, i would just go out and buy a more modern powerful car.
The other way to do it is to sell your car and buy a cab that already has that engine fitted to save yourself the work.