Ok got this done today. So I decided just to remove the cross-bars first before removing the exhaust. For future E93ers, to remove the cross-bars you'll need a 17mm & 18mm socket to go along with the 13mm socket that you'll use later for removing the exhaust hangers.
I first loosen all the bolts before putting the car up on ramps. I was surprised how easy they were to loosen, I used a 1/2" drive breaker bar but I probably could have gotten it loose with just a ratchet.
There are 4 17mm bolts and 1 center 18mm bolt that meet near the rear diff. Next to each rear wheel is a 13mm bolt and then another 18mm bolt underneath both sideskirt.
Once everything's loose and the car is on the ramps you can remove all the bolts under the car. Then you can pull each bar out from the undercarriage panel and begin removing the exhaust.
After you install your new exhaust just bolt everything back up and you're good to go. I used a small stool to hold the bars up under the diff while I bolted everything up.
On a side note - I'm more than pleased with how my modified OEM exhaust turned out. It sounds ridiculous with the top down. All vert owners should do this mod ASAP. This and the spacers should be mandatory.