Are there really two different counterweights for the two different engines. The company that I ordered mine from only had one, and when I called my local mazda dealer they only had listing for one counterweight, and didn't specify s4 or s5. I was
reading another thread though, and read that there were one for each. Any ideas. Who is wrong.

 

the early Turbo car 1986 - 1988 has lower compression and different weight rotors so has a different counter weight to the 89-91 turbo. i fitted the wrong one and had a slight wobble.

not sure about non turbo

 

yes they are different.

11-521A-N327 (s4)
and
11-5210-N351 (s5/FD)

 

Called the company that sold me the counterweight, and they had no idea which one it is they sell. It was a lady, and didn't seem to have much knowledge of it are how to figure it out. The one I bought is already installed. Will it be easily noticeable if the wrong one is on there. Also the mazda dealer looked it up by year, mines a '90 did they make s4 and s5 for that year.

 

Does anybody know if it will be noticeable driving if I have the wrong counterweight on there? Will I be able to feel a shake.

 

Yes, you will have vibration problems with the wrong counterweight.