So my car is still up in air awaiting re-installation of its front control arms but I installed the collars last night and I thought I'd share some observations.
First, Ghost's writeup in the first post is dead-on. No guesswork needed if you just follow his directions.
All of the subframe nuts/bolts were very tight but the fronts were relatively easy to loosen. A breaker bar or a few ugga-duggas and they'll come loose no problem. The rear subframe however was tightened by very strong and very angry robots. The front bolts of the rear subframe could be loosened by my air impact after a bit. The rearmost however, neither my electric nor air impact could make a dent. I eventually had to use a breaker bar with a pipe extension for more torque. And listen, I'm a 255lb weight lifter and I still struggled. I was scared I would shear the stud off before that damned nut would break loose.
Speaking of that rearmost nut, it's on a very long stud that's only partially threaded. Buying a super long 19mm socket like Ghost did is the easy, non-destructive solution but I already had a Dremel with heavy duty cutting wheels so I just cut off the non-threaded portion. 5 minutes per side and done, no big deal. As always, when using a high speed spinning tool, wear eye protection.
My front subframe was definitely mis-aligned. I had to loosen all four bolts and use my hands and knees to shift the whole thing over and back before I could get all 4 collars into place. This illustrates that the subframe is held in place only by clamping force and not interference from solid material. So, especially if you have sticky tires, an aggressive alignment, control arm bushings, etc, the subframe could definitely be pushed around. The collars will prevent that.
When putting the collars in the rear subframe, the fronts popped right in easily. The rearmost subframes holes however are more of an oval-shaped slot and the collars have to basically be smashed in there by tightening the nuts. The right side went in without drama although it's definitely never coming out without some serious persuasion. The drive side however, I could only get the collar about halfway down into the subframe hole before I was afraid the required torque was going to start stripping threads off the stud. I think it'll be fine as the collar is in far enough that the subframe can't move laterally and I torqued the nut to probably 100ft/lbs before I chickened out.
I'll post driving impressions when my car is back together and aligned, whenever that may be.
