[Capt Spaulding]

A couple of things. First, as others have said, the diff inserts do a lot to reduce drive train lash and "wind up." I have the subframe inserts in my "project" box in the garage, but have not yet persuaded myself they are worth doing.

When I was closer to doing the subframe, I took note of the number of people who have had problems with the subframe bolts cross threading on reinstallation. I looked closely at the installation and concluded that the cross threading problem is caused or at least exacerbated by doing the two ends of the subframe in isolation.

When you install the subframe inserts, you support the subframe assembly on a jack. If you snug the jack up, remove the front or rear bolts alone and the lower the jack a bit you can get the inserts in. But because they add thickness to the mount, and the rear of the assy is still bolted to the car they add a small amount of angle to the whole assy. When you try to reinstall the bolts, that added angle will try to cant the bolts slightly. Thus, the cross threading.

My advice is to support the assy with the floor jack, loosen (but do not remove) ALL the bolts about half way, lower the jack slightly, remove one set of bolts, install the inserts, then hand thread that set of bolts in 1/2 to 3/4ths of the way. Do the same thing for the remaining inserts, then raise the jack until the mounts are just touching the frame and hand tighten ALL the bolts as much as possible, then raise the jack to fully support the assy against the frame and torque the bolts.