So back on topic, so far I only got one diamond B&W tweeter and put it in the center, but honestly I can't hear any difference vs the Bimmertech tweeter I was using. This is probably the result of the filter that I am using.
I am looking at other tweeter options online, I see the Infiniti and then there are more expensive tweeters such as Audiofrog, Hertz and JL audio that seem to have rave reviews.
https://www.crutchfield.com/p_301ML2...-ML-280-3.html
https://www.crutchfield.com/S-7RC066...IaAkpeEALw_wcB
https://www.crutchfield.com/p_136997...ct-Single.html
If I was to go with these, what kind of crossover/filter should I use? Luckily in the X5 the tweeter plugs right into the midrange, so it gets the full range of frequencies that the midrange gets, and then I need a crossover/filter that can filter out below the tweeters frequency response. With the Hertz tweeter, its response its 1,000-25,000 HZ, which is pretty amazing.
There are also Focal TBM utopia for $1,750 that have frequency response up to 40,000hz - but they are probably a complete waste with BMW's subpar amp/dsp.
https://www.crutchfield.com/p_091TBM...BM.html?tp=107