you might consider, specially for long trips, buying the Bmw cotton seat covers(or something similar)..not cuz they're so beautiful(not)..but to sew a flap/slot in back to hold your support device...no damage to the leather and custom comfort would be yours...sewing skills?..you don't need 'em..you could easily hand sew/or even glue something effective...dk '97 2.8 bg R