This is a post from the alpine rep in the DIYMA thread posted earlier.
Once you disconnect from the PC, the presets are saved in the H800 and the W910 will be able to adjust:
1) Presets - need to be saved from the PC Software
2) Balance/Fader - pressing the "speaker" soft button on the Audio screen of the W910 will bring you to the balance fade screen
3) sub Level
That's it without the RUX. The real intention (and it won't ring true with most here as we are crazy tweakophiles) was to give the installer/shop the ability to tune the car, set the various presets and give the customer the control he needs without the ability to change the tune, so doesn't come back and say "I didn't touch anything but my tweeters are blown...and the shop[or mfg] is stuck with the bill" or something along those lines when you give them too much control of everything.
As for me in the exact opposite, i would much rather not have to pull out a controller to tweak and would much rather have it integrated like the 701 was with the 205/505. alot easier for me to adjust settings on a 7inch screen then it is a little single din screen
Also this tidbit is the most appealing to me
The H800 does not use Audyssey tech this time around, this is our new ImprintEQ developed by our Japan HQ team. It has significantly more resolution, especially in the mid and lower bass, plus it has user definable/adjustable target curves.
The H800 also has Euphony, which acts similarly to Logic7 in that it can create surround sound from a 2ch source
So there you have it , its a totally new imprint system and they ditched audyssey and there is the only reason you can tweak after imprint. Audyssey is very about lettin you play with there curves even in the home enviroment.
All in all sounds like a nice addittion