Not sure how they will sound with the factory amp. BMW sends certain ranges to each of the front speakers (highs,mids,lows) and the speakers you have may not respond as well. Another thing to keep in mind is that the factory mids are 2". I'm not sure what size the RF's are, but there may be fitment issues. There are a few threads in the stereo forum regarding speaker replacement, you may want to check those first. Good luck, let us know how it turns out as I'm going to be replacing my speakers (sometime). Post pics!

Here's the most recent thread I found, hope it helps: http://www.xoutpost.com/stereo-system...placement.html