I started installing my S&W cage this weekend,and need some answers.
I dont have a headliner, it tore apart years ago. How much room should I leave between the main hoop and the T-top center brace to allow the headliner to fit back in? Can you install a t-top(ABS) headliner after a 10 pt cage has been installed Do you have to cut the plastic interior panels where the main hoop welds to the floor?

 

I don't have interior so I have no suggestions for the headliner. Looking at how high my main hoop is, I don't really see why a headliner can't be reinstalled. My halo tube is installed so that I can still remove my t-tops.

The main hoop doesn't get welded directly to the floor. You need to weld 6" x 6" x 1/8" steel plates to the floor. They don't have to sit flat so you can bend and shape them across the floor area to make them fit. The tubing is then welded to these plates. That way you have a plate with 24" of weld holding it to the sheetmetal. I have no idea what plastic interior panels you're talking about. The best position for the main hoop is on the hump behind the front seats. You can't position it to far outward or it becomes difficult to weld the backside of the tube.

 

I am going to use a 8x8 plate, so i can form it forward over the back seat crossmember and also tie into the rear subframe. Also going to plate the whole hump for the diagonals instead of just the small plates on each side. I cut 4" off the main hoop and right now it still touch's the t-top box in the center. Just not sure how much more I need to cut down so the headliner will slide in.

 

I don't have the ABS one since mines a hard top, but the cloth one slide in through the hatch with about an inch of space on the main hoop of my roll bar.

I also mounted mine where the rear seats use to go, so my driverside seat could be all the way back and reclined slightly. I had to notch/cut the plastic below the sail panels after it was all done. So yes if you plan on installing it there you'll more than likely have to cut some plastic.

My kit didn't have plates for the diagonals but I just cut one of the 6"x6" for it and got a replacement from the weld shop.

I also had to notch the passenger side door cup holder because I didn't like how the bar moved inwards so far to clear it.

 

I didn't have to cut any plastic at all with my S+W kit. You can see in this picture it all sit in front of the plastics. They wern't even tight either.

My car is a hard top and the headliner for the most part slid right in. The only problem I had was that the hoop by the front windshield is positioned so far up and out of site that the headliner didn't fit past that part. I had to cut it back to go all the way in. It was a small sacrifice to not have the hoop in my face.