I've finally got the Empeg most of the way installed into my 2001 330i, so I am confident it can be done in you 1998 535i. I don't know if this is a Scosche dash kit, but there's probably one out there in addition to this one. The Empeg sounds pretty good but I would recommend picking up some high quality line drivers to bump up the volume as it's a little faint. If you find some good ones, let me know because I am still looking.