Three weeks ago I finally completed my enhancements to my 2004 x5 4.4i (with NAV and DSP) and want to share my experience with others who may be considering an upgrade. Here are the upgrades I made together with my comments on their performance:

1. Knocked out all 10 stock speakers and replaced them with Rainbow Audio speakers offered by BSW + midranges sourced and offered under BSW brand. For main drivers I went for a better version than ones listed under Stage 1 upgrade, for additional $30 per driver. Factory CD Changer and Amp were left intact.

At this stage the improvement from stock system was HUGE. I am a serious audio enthusiast and to me the stock system was simply unlistenable and a headache catalyst. The Rainbows removed the entire muddiness and gruff out of the system; improvement in highs were signficant, with crisp vocals and excellent rendering of strings. What was more surprising was the low end; I disconnected the junky factory subwoofer and found the bass quality of the drivers to be truly impressive. However I do think that the way the factory amp crossover is designed, you will not get optimal sound w/o a sub. Before I move on to the next upgrade details, I want to specifically commend the BSW guys for delivering an "excellent" midrange set. They excelin voice rendering. I think my installer screwed uo by bypassing the crossovers that were provided with the install kit, unless i am unclear abt the technicalities, but as is, they sound fantrastic - especially when I listen to jazz or new age vocals.

I have no experience with MB Quarts, but I can tell you that Rainbows will impress you. My higher end Rainbows were the most expensive option, but I am extremely pleased with my investment and think every penny was well spent. Caveat though, I still have to address the brightness issue with my midranges, which I think is an install issue.

2. Next step was the subwoofer upgrade from BSW. I will keep it short - if you change your speakers and do not change your sub, it makes no sense, as you dont get optimal results. But if you go all the way, you will be amazed with what you hear. BSW should be proud of creating this niche product that fits like a glove into your beloved BMW and sounds like heaven. This 8" sub is fantastic; expensive but, hey, try creating a stealth setup like this from scratch and see what you might spend...and what you get.

3. Last was DICE + Speckdock. In short, i will call it "DICEY". It's a disastrous product that insults and abuses the otherwise fantastic system in my X5. When I swapped my CD Changer with the DICE, all the muddiness and headache returned with a bang. Mind you, all my music in my iPod is in lossless format cut straight from my own CDs. After this dissapointment I switched back to my CD Changer. This convinced me that I would rather live with the limitations and inconveniences of my CDC than to destroy the potential of my otherwise great system. My personal belief is that DICE is a great concept that is executed very poorly, and is targeted at "interface" junkies who cant tell sound quality from a rat's ass. Probably just the kind of people who use stock headphones with their iPod? Jokes apart, I think the poor electronics and the really long run of cheap cable from front to back are to blame for the dismal performance. I am returning them.

Finally, I went out and bought a Sony Cassette adapter for the iPod. Hear this; the cassette adapter delivers "far superior" output than the Dice. It hides neatly behind the Nav screen, the wire can be concealed (i havent had the time to figure that but surely will), and for $30 you are able to keep your CDC and date your iPOD. This combination rocks. Believe me and try it, you will NOT regret. Since I have no experience with FM transmitters, I cannot offer you an A/B comparison, but to my discerning ears the cassette adapter is a great solution.

I hope this helps you prospective buyers out there. Go deck up your beloved darling and enjoy the drive. Ciao.