Problems with direct injection

We know that the boxer will be equipped with normal & direct injection, probably 8 injectors total. Lets gather some facts/problems about DI, since we`re going to get our hands dirty. I dont know anything about DI, but here`s what I found - it builds up carbon on valves pretty fast: [img]http://i140.photobucket.com/albums/r34/saaber1/glivalves.jpg[/img] [url=http://i140.photobucket.com/albums/r34/saaber1/4cylindervalves.jpg][img]http://i140.photobucket.com/albums/r34/saaber1/4cylindervalves.jpg[/img][/url] [url=http://lh5.ggpht.com/_eLw3nFw4Esw/SzjpokK-rlI/AAAAAAAAAxc/0uQMyyJ_h2s/s800/IMG_2171.JPG][img]http://lh5.ggpht.com/_eLw3nFw4Esw/SzjpokK-rlI/AAAAAAAAAxc/0uQMyyJ_h2s/s800/IMG_2171.JPG[/img][/url] [url=http://i483.photobucket.com/albums/rr196/jhines_06gli/GLI/valvedirt3.jpg][img]http://i483.photobucket.com/albums/rr196/jhines_06gli/GLI/valvedirt3.jpg[/img][/url]