I just installed a rebuilt set yesterday on my 3100. I tightened the side plates just until I knew the new rubber bushings were properly seated. I "securely" tightened the frame brackets as per manual. My suggestion if you've never reinstalled these before, is to loosen your front mounts and keep all the mounts loose until you have them lightly bolted in place. I also used a large dfift to help line up the frame bolt holes to the brackets. I plan on retightening all the bolts after some use and also check the clearance alighments then when they have settled out.

Drew