No they fit different, although mk2 and mk3 and some mk4 polo gearboxes will fit. You want an 8P gearbox.
Yes, I have it done on mine. The MK3 2.0 gearbox fails when it gets to high mileage. The Mk2 1.8 gearbox is bulletproof.
yes they will
Nope
yes as long as they are the same stud fitment. The mk4 golf is 5x100 bolt pattern and the mk3 golf is 4x100. unless it's a vr6 model which has the 5x100 bolt pattern so in general the mk4 wheels will not fit a mk 3.
No they do not. The Mk3 uses an entirely different headlamp as compared to the Mk4. They will only fit if you swap the front end of your Mk3 with a Mk3.5 Cabriolet. Furthermore, Hella Makes Headlamp units that look very similar to the mk4 headlamps.
no
It's located on the top of the gearbox -- has 2 wires going to it.
IT SHOULD BE A STRAIGHT SWAP PROVIDING 98 GOLF IS A MK3.
Yes, albeit new engine and gearbox mounting need to be fabricated.
if you need to ask then i would get someone who knows what to do as it ain't a 5min job but it ain't hard either but not for the beginner to do.
Yes