I put the 8 point cage in my late B a few years back. This is a big unibody car that they don't make anything off the shelf for ( cage / subframe connectors). Before the cage install, I was running mid 11's and starting to wrinkle the rear fenders by the B pillar posts. I installed a highly modified E body 8 point cage. What I did to stiffen the middle of the car was to add a bar near and parallel the floor between the main hoop and front down bars ( pic). Since my main hoop sat over the front part of the rear frame sections and the front down legs sat over the rear parts of the front frame sections, I essentially made a box over the area where there was no frame. I was going to fab up some sub frame connectors, but decided to try it without them. I still might in the future, but the car now runs mid 10's with no body flexing that I can visually see.