I know what you mean when it comes to rock and metal. There is somewhat of a gap in the audio spectrum thats missing. Luckily though, my IDQ's seem to even it out really nicely. I love listening to rock in my car.I listen to a lot of metal and personally I thought the Reference set I had was pretty much garbage. It's hard to complain when they're under $100, but that was money that I could have used for something significantly better.
Those Blaupunkt tweeters seem very nice. How much did you get them for?
I bought them off a forum member for $60. Brand new.
I read reviews and people seem to like them alot.