The iconic hot hatch will be offered with a new 2.0 turbo petrol engine with two different power outputs: 217bhp and 227bhp.
The low-power engine will be in a standard version of the new model. It will be able to crack 0-62mph in 6.6sec. New features include a progressive steering system that's designed to be light and easy while manoeuvring but more sporty and direct at speed.
The lightweight MQB platform that underpins the car and the new engine help improve economy over its predecessor to a claimed 47mpg.
VW R&D chief Ulrich Hackenberg describes the new model as "Low weight", offering "outstanding performance in a car that's both comfortable and sporty".
The 155mph 227bhp version of the GTi will come with a host of other upgrades for a more focused drive. Hackenberg said: "It's not just performance with the more powerful model - there's a new differential and bigger brakes, too."
"The Golf GTi has always had a small power increase - 10bhp each time in recent years. We could have done more and there are those who want more, so we now offer another 10bhp for them and also a huge increase in torque - 70nm (52lb ft) - in addition to the 10bhp.
A Stop/Start system will be fitted as standard to all versions, with a six-speed twin-clutch DSG gearbox an option.
Tests of the new Golf GTi on the Nurburgring have proved it to be 13sec quicker than its predecessor.
Hackenberg revealed to Autocar that "The real thing will be seen at the Geneva motor show next year with some very minor detail changes. The same goes for the new Bluemotion."