Sorry - worse with the stubby! Although the stubby has been on my 2.5si about 3 years and I've only switched to the other aerial half a dozen times (e.g. on some parts of the the North Coast 500).
Z4MC has the official BMW sports aerial and it's a bit better, but still not as good as the whip.
I've used these on 3 cars now all with satnav and worked fine no poor fm signal. The long aerial is specific for the satnav though to get best signal
I've used both genuine bmw one and cheap ones both same quality I thought had no problem. In fact I snapped my first long aerial on E46 and the stub end was stuck in so and unable to get it out. I couldn't remove the base for nearly a year until I found away to unscrew it from underneath right pain. My satnav and radio worked fine without any aerial in at all. If u have bad signal wires could be touching the metal on stereo which gives poor signal
