Not too tight..but at the same time not too loose. If you are really trying to do it as tight as possible and doing anything you can to get that then lossen them up..it wont solve your problem. May make it worse.
Crunching is a new one...But...Check all the parts for movement..if you pull things about you should be able to feel it..but it will only be very slight. If anything is wobbling slightly it could be the bushings..they dont last long. They may need replacing. Check there are 2 white spacers between the bolt thingy and the sping. If you have lost one that could be your problem. Then I would just spray some silicon spray (or something silicon based) on all the joints, see if that does anything.
Somebody else may be able to help you better than me..I have never known crunching.. Sure its not a click or squeak?
EDIT: btw, could you make your sig a bit smaller please. Big sigs make the pages take ages to load for some people.