You have an MK4 jetta, MK3's are 93-98, MK4 is 99-05. MK3's also didn't come stock with the 1.8T. MK3s are also super flat incomparison the mk4s.
Simple answer is yes.
1998 Mk3 1999 Mk4
Yes, if they are from a GTI or VR6 mk3. Ordinary mk3 wheels are 4 bolts 4x100, while gti and vr6 are 5 boolts 5x100 same as mk4.
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, the floor pans are completely different. The MK3.5 will fit the MK4.
just about everything
yes they will
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 fit different, although mk2 and mk3 and some mk4 polo gearboxes will fit. You want an 8P gearbox.
Make sure that MK3 is 5 stud as they have 2 different stud patterns - 4x100 and 5x100. Mk4 is 5x100 pcd (bolt pattern). So make sure you have the correct fitment.
yes it will if you buy wheel adapters you will need 5x100 to 5x120 BMW if you have a mk3 or mk4 jetta depends if you have mk5 you will need 5x112 to 5x120 but you can fit Mercedes rims on a mk5 so why bother
No they can not. I made the mistake of buying some but they are completely different from MK4's so don't waste your time.