Originally Posted by XLR8SN

I think that the fix might be to open up the inner diameter of the knob area. If you turn it upsidedown...there are 2 step down "holes". One is to clear the shift post and the other step down area is where the threading starts to screw it on. Its the first "hole" that clears the shift post that might need to be opened up like maybe 2mm or so. I think that the vibration from the transmission is causing the shifter linkage and post to oscillate and just touch the inner portion of the knob causing the metallic vibrations at high RPM's.

I bought the delrin version as well to test this theory out. It should arrive to me next Monday or Tuesday. Will change out the shift knob and post results.

If it is the knob itself...then using the delrin one should eliminate the vibrations since it is technically a polymer...aka...plastic.