I almost exclusively use the Xtrons headunit for CarPlay, however on the occasions that I have a need to do something else I find the default Xtrons launcher to be a pretty jarring experience. I've been having a bit of a look around at options, and have had a play around with iDrive Launcher (https://idrive.ibus-app.de/index_en.html). I know that NBT iDrive didn't come on the E46, however it certainly feels a lot less flashy and feels like it fits much better in the E46 than the standard Xtrons launcher. I think it's an acceptable compromise, given I've already compromised by putting newer technology in the E46 anyway.
I have to say I'm super-impressed with the software. It's very nicely built, fast, reliable, configurable. It's a pretty nice experience to get in the car, turn it on and see the BMW boot logo, then the iDrive launcher home menu, then have CarPlay auto-connect.
I've got more work to do to sort out the menus (I don't need the Multimedia, Navigation or ConnectedDrive items for example) but will get that sorted once I've got everything figured out and optimised.
I'm also working on mapping the second (right hand) control knob on the Xtrons unit to the navigation controls for the launcher, if I can get this figured out it means the interface can be controlled with the control knob/SWCs which would be a nice added touch.
Here's a few average iPhone photos - doesn't really do justice to the super-smooth animations/transitions, but you get the idea.
Interestingly these photos also show that I haven't quite got the RGB/luminosity of the head unit illuminated buttons right. I 100% can't tell in person, but the photos clearly show it up - will have a play to get it closer.