starter wiring

Hi guys, I,m just posting my first thread. First problem is that I have replaced 9 starters in my 1990 jetta 1.8 engine. I am aware that there are two different starters for this model. The mechanics say the car is wired wrong and thats why it keeps screwing up the starter solonoid. This Jetta has a starter relay and they say it shouldn't be there. Were these Jettas wired wrong in the factory.
Starting To get frustrated over replacing another starter... they are a B&%$h to change.

What is actually happening to the starters? Has the starter bushing been replaced? Often people will install a "booster" relay to help with current draw issues.