Would it be too tricky to fit my newly acquired milltek at home with the car on stands/ramps? the back box is huge, and I think id need to cut my stock exhaust off too.

Not too tricky done it a few times. Need to get car as high as possible to be able to swing exhaust over the rear beam. You may need to cut off /angle grid std exhaust. Of course much easier on ramps but not impossible on axle stands.