I particulary have been using Defi Amber BF imperial electronic gauge with its controller. That is what I am using currently on my turbo cars and that is what I will put on the BMW.
Not only I think this gauge is a must but I also consider it a tuning/diagnostic tool. The Defi electronic series can record boost for up to 3 minutes and also record peak boost and other funtions like peak boost warning. Last but not least it matches with the BMW dash illumination.
