While I was changing out the guibo (which I have to post some pictures of, it was shredded!) I noticed alot more carbon buildup in the front downpipe, from the front 3 cylinders on the engine. Does this indicate anything in particular? I don't use any coolant at all and not much oil, maybe half a quart in 3,000-4,000 miles. Just curious as to whether anyone else has seen this?