I just installed Energy Suspension poly bushings and end-links on the front and ES poly bushings and rubber end-links in the back. My question is this. How do I know when I have the end-links tight enough? Or, conversely, how do I know if I have them too tight? TIA

 

Tighten them until the nut bottoms out on the end of the threads. (meaning tighten 'em until they don't tighten any more)

 

crank 'em down. hmmmm..... okay

That's what I did to the rear ones and now I have a "twangggg" sound like a tighlty strung guitar string back there.

 

No, peejay must be talking about something else. If you crank em right down you'll squash the hell out of the bushings.

Just install them as per the specs in the manual... 13mm of threaded rod showing in the front and 5mm in the back.

 

Thats with rubber bushings. Tighten the polys just enough to take out any slack should be fine. Also don't do it with suspension hanging either. IE don't jack it up at the frame

 

It would be easy to deform the rubber bushings but the poly bushings up front are tough as hell. I didn't crank the rears all the way but I did tighten 'em down pretty good. These aren't OEM Mazda parts and i f I went by the manual and left 5mm showing I think they'd be pretty darn loose. As they stand the bushings don't look deformed or anything like that. The car handles great but like I said, I get this "twang" vibrating sound out of the rear at times. I guess I'll loosen them up a bit and experiment a little.

 

You tighten them down to much and it will start to pull the body down . Just snug therm should do it

 

I wasn't so much worried about deforming the bushings. It's just that there's no need to crank them down so tight that the bushings balloon out the sides. Anyway, sounds like you have it sorted out.