it depands on the year
Yes, it is a Golf but VW stopped calling it the "VW Golf... GTI". Just as VW didn't call the R32 a Golf (although it is based on the VW Golf and has the same shape and many common components).
where is vw golf gti engine number
4x100mm
172 HP
yes
if you're speaking of the R32 it is a 3.2L 6 cylinder with 240 horsepower. If you're speaking of a regular golf it has a 2.0L 4 cylinder with 130 horsepower. If you're speaking of the GTI it is 1.8 turbocharged 4 cylinder with 160 horsepower.
174 hp at the crank
Reviews on the VW Golf GTI MK4 can be found on Performance Car, Consumer Reports, Car Guys, Car Advice, Review Centre, Scooby Net, Drive and VW Forum.
Dipstick should be marked
5x100 mm
starter relay location
Sadly your out of luck, it uses deisel :(