Buy a 2003 Golf gti 1.8T or a 2002 Golf 4MOTION V6

Stick with the 1.8T, it's the better platform for performance stock and if you wanted to tweak it and it's gonna be a lot easier than swaping in another motor.

Cheers Nick, But I'm thinking stock for stock, will the bigger V6 engine not deliver smoother power through the rev range than the smaller all be it, turbocharged 1.8 litre engine?

It does not put down as good of power numbers, also you have to think about what else will be entailed in the swap. you will have to do the motor obviousley, but you will also have to change motor mounts, coolant hoses, the wiring harness and ECU, if it's an auto possibly a different torque converter and flex plate, if it's a manual trans then a clutch and flywheel. It's going to be a lot of work.