The quality on the STS motors is sub standard in my oppionion.
The problems you are describing sounds to me like the P/S is worn out, if it is go get it pinched.
As far as the CVD`s go.......I run the rear ones on all 4 corners, you can narrow up the front end to 195mm. More steering!
As far as wear on them, I have worn out a set of one way & rear diff cups allready the uni`s are still fine.
Freefall girl............I bet beeing a woman you have more things to do with yourself!