yes, indeed this could be a serious problem.
You say your car is a '93 right?
You say the retainer they put on is for a '94 right?
Here is the problem. The retainer for the '94 is different than you need for your '93. What is different? the one for the '94 is longer, because they changed body styles in '94 and moved the shifter hole back more. In order to move the tranny back they made the bellhousing longer, which in turn meant a longer input shaft for the tranny. It's not much longer, but that steel retainer in your car is sticking too far out, and probably interfereing with the clutch disk/pressure plate. Are you experienceing any noise?
If you don't believe me check out summit or jegs or anyone that sells the steel retainers. The break is '93 to '94
So if the information you provided is correct, that retainer is probably what caused the problems.