That's good news about the SD slot - I was interested in using that as well. Although, seeing that the iPod interface is pretty good, I might break down and buy one =\
(Oh, and I have a 2010 WRX - It looks good in the dash of your STI =D)
I do have some questions regarding using the unit at night:
Does it dim with the interior lights, and can you adjust the dimming? One of my biggest complaints with some aftermarket radios is that they're too bright at night.