Originally Posted by Modshack

Yes there have. Some of the pictures I've seen have not been pretty.... With direct injection the valves no longer get a flow of Gas which serves to keep them clean. The only air you get is mixed with Blow-by and contaminants (oil) from the PCV system which builds up on the valves and stems. I think Toyota employs an additional upstream injector to deal with this, but most don't. Pics of the VW 2.0 FSI and the Porsche Cayenne have been ugly.. Careful what you wish for.

Here's a pic of the VW/Audi 2.0 with direct injection (mileage unknown):


Here's a shot of the 1.8T (the engine that preceded the 2.0) with conventional injection, use of good gas, at 125,000 miles..