Rear passenger side lower by 1/2 inch?

[imjusthere]

I recently bought my first e30 and the rear passenger tire rubs the outside fender when going over larger bumps. On closer inspection the passenger rear side is 1/2 inch lower than the drivers side. What is the proper way to fix this? It has Bilstein sport struts and Ireland Engineering stage 3 springs. I've been told that my subframe bushings are fine but that my rear trailing arm bushings need replaced. Could that have anything to do with it?

[digger]

probably, needs to be fixed in anycase

[imjusthere]

I plan on changing all the rear bushings but I don't know that that has anything to do with it. Any ideas?

[imjusthere]

Anyone have any ideas what could be causing this?