How do you spec the front suspension on my 89 535i? I have had the bimmer for one year now and the passenger side strut is bouncing. Want to replace struts, springs, spring seats and strut mounts. Question is how do I tell if I have a lowered 535i? I have heard that with Bilstein struts you are not suppose to use bumpers? This is all very confusing. Any one out there found a good combo for all these parts?