Volkswagen: 1992 vw, jetta gl, digital fuel injection

Question
I have a 1992 jetta 1.8L gas (w/ a/c).My problem is that this car is an import, bought and made in Germany, shipped over. Over the years the parts brought in never fit and need to be modified, no mechanic seems to understand that it is a jetta, not a jetta gl or gt etc.I have spent thousands just over the last couple months just to keep this car on the road. The teeth  on the ring gear of this are badly ground, some almost gone. It grinds horribly sometimes 10-15 times before starting. I know that 1990 and previous domestic made vw's had problems with the starter and ring gear properly engaging. This is a 1992!? We have replaced the starter twice thinking this would cure the problem, it has only gotten worse. Recently I found out  the only rebuilt starter for a 92 jetta will only worsen the ring gear problem and that we shouldn't have replaced the starter to begin with. Furthermore our car will stall at idle and while driving,will not quite turn over for awhile after that.Not to do with starter problem.Both fuel pumps, ignition module and spark plugs have been replaced.What should i do? Thanx for your time and consideration!

Answer
if the teeth of the ring gear are worn, then you have two choices. replace the ring gear which is a very difficult task. or replace the flywheel complete. the flywheel cost's more to buy, but ultimately is cheaper to replace and more reliable. as for the cutting out, is the car carburated, single point injection, mechanical fuel injection or digital fuel injection.