Though not much larger in stature, the GTI gained about 400 more pounds over its predecessor, partially due to the inclusion of more safety features and partially due to increases in creature comforts.
Indeed, this was the first (and only) generation of the GTI to feature Volkswagen's 2.8-liter "VR6" V-6 engine. Power is up to 172 horses for this generation, while torque jumps to 173 pound-feet. In the late 90s at least, there was no replacement for displacement.
While a larger version of the VR6 found its way under the hood of the Mk4-based, all-wheel drive Volkswagen R32, the GTI downsized to a 1.8-liter turbocharged and intercooled four-cylinder engine mated to a six-speed manual transmission.
Power is up to 180 horsepower and torque is up 174 pound-feet. The Mk4 is the first GTI to feature a turbocharged engine, but it won't be the last. Zero to 60 mph increases slightly to 7.2 seconds while the top speed grows to 135 mph.
The Mk5 GTI debuted in 2006 with the signature goatee grille that still influences sport compact car design today. (I'm not really a fan of the look.) VW built 46,558 of these between the years 2006 and 2009.
The extra power is necessary because the Mk5 also gains about 350 pounds of mass over its predecessor. Still, zero to 60 runs have been shortened to 6.7 seconds. Top speed remains in the 130 mph range.