I have been looking for the exact same thing but the best suggestion I have had so far is to sell the OEM and buy a new changer to match my HU. I believe the OEM changer (I also have 99 328i) is an Alpine but I am not 100%
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.