stock HU must go?

I keep trying to adjust my new components and sub but can't get the sound I like yet. I'm getting a set of ADS crossover for the components in front just to see if the Audiobahn 18db slope crossovers are set too low for the tweets.
I hear too much uppermid in the tweeters and that muddys the upper tone while making female voices a bit harsh.
I'll try the new ADS crossovers which are 12db and crossed at 2700Hz.
But, that may be too low as well. I seem to prefer tweets sets are
3000Hz and above.
The other option, if the ADS doesn't work, is to custom the ADS cross points with high quality film capacitors.

However, I feel I may be chasing phantoms with this crap BMW system.
I'm beginning to think the stock HU is just crap and I'm trying to fix my audio from the wrong end. Maybe I should try a new HU and then see what may need tweaking. Any opinions on the stock HU and it's lack of quality?
Have you tried a new HU while keeping the rest of the system alone and getting a HUGE difference in audio quality such as frequency reponse in CD and tuner modes, sound stage and depth, overall clarity, better bass imaging, etc...?
I'm going to suspect so, but I'd like some input into this.

Thanks for input.

TT

Well, here is my experience. I get better sound, but you will have to go back to step one and start retweaking everything!
THe adapter kit didn't fit my Kenwood Excelon unit right (the little plastic ring makes the adapter kit "bow" out and it looks like crap. (gotta work on that) You will have no FM reception with the aftermarket head unit, some folks say get an amplified antenna - others say get a new one. I have mine hooked up to our stock antenna and I get ONE station.
So...Id try the Xover first. I had my stock HU with JL components and it sounded great! I wanted an aftermarket for SAT radio and MP3s.
Oh you will have to get the PAC SWIX to use your steering wheel controls also.

I agree. I'll try the crossover tweaks first and see where it goes from there.
The big problem I have with the stock head unit is the tuner section.
It's not very good at reception. Many strong stations in the area still come in with a bit of static with the changing weather conditions. This stock HU seems very susceptible to changing radio station output. The stock Infinity head unit in my Mits Eclipse GT was awesome in comparison to the BMW unit.
Reception was rock solid, it had a 4 disc in dash CD changer, bass treble and midrange control and the CD player had better signal to noise.

I don't care much for the steering wheel controls really. I use them very rarely. The HU controls are so close to my right hand that I don't bother with the steering wheel controls. The other aspect of the wheel audio controls is that they are very stiff, too stiff. I don't understand why BMW choose to make those controls so stiff. You can't just touch the buttons to use them, you have to actually push on them.

My new ADS crossovers should be here by this weekend so I'll get a chance, maybe, to try them this weekend. They appear to be very nicely made.
The only thing that concerns me is that the ADS crossovers are 12db slope whereas the Audiobahn's are 18db, or so they claim. But, it looks like ADS uses better "poly" capacitors.

Thanks for your input.

TT