Rear Suspension Troubles

[1823alex]

I've recently acquired a 2003 4.6is imola rot with relatively low miles (well the lowest mileage old bmw I've owned yet lol). At 110k miles when I purchased it I've been slowly combing through the truck to get it back to proper road tripper status. Anyways the truck is on OEM sized tires on style 87s. 9.5" wide front rims and 10.5 wide rear rims with 275 somethings up front and 315/35/20 in the rear. Now the previous owner did a air to coil spring conversion which I'm not a fan of since they went with cheap Chinese parts. Ever since I owned it it's had an annoying rubbing noise in the rear passenger wheel area. I found the aftermarket spring is rubbing up against the chassis on the outer wall of the area the spring goes up into. I plan to convert the car back to OEM air suspension as I already have most of the parts on hand and have new arnott airbags. I also removed the previous owners rear wheel spacers as I was getting some awful rear camber wear too. After removing the spacers i now have just the passenger rear tire occasionally rubbing on the inside part of the chassis. Now I know the rear suspension needs a refresh of sorts so I decided to purchase adjustable rear camber and toe arms from silver project eu. I'm hoping this will solve my uneven tire wear issues. However I'm concerned that when I install the new air bags in the rear that the air bag might still rub on the chassis. Has anybody else ever had any issues like this before with rubbing on stock wheels and tires? I don't want to put the new bags in and then have the passenger rear blow out because it's rubbing against the chassis too much.
There were no Carfax reported accidents, the truck was taken care of relatively well until it seems about 80-90k miles as it had some sort of CPO contract and got some things replaced under that but unrelated to the suspension. To be clear it's quite a multi part problem the inside of the rear passenger tire only runs on the inner chassis wheel liner, and the spring itself that was added for the coilvoer conversion rubs on the outer part of the chassis right where it begins to go up by the mount

Is it possible I need new subframe bushings and that the frame could have shifted over, is that common? Or can really badly worn rear control arms cause stock tire rubbing on the inside of the wheel well? Would this also cause the spring to rub on the chassis or could that just be a case of installation error? I can't imagine it to be that hard to position the spring on the perch correctly and what not though, although the most recent owner has surprised me many times with their hackjobs on the rest of the truck.

In addition to converting back to OEM rear air suspension I'm planning to replace the rear shocks, shock mounts, and add adjustable upper and lower control arms for rear toe and camber adjustments. Will this be enough to solve my awful rear tire wear and rear end rubbing noises?