On gross inspection they are noticeably larger though only a 2 mm increase in bore. The install is sort of intricate. Dinan states 11 hrs labor. My shop did it in 6 hrs. but the job was far from over. The car did not run right, loss power and the CEL came on. The throttle bodies had to be synchronized. Finanlly after getting the proper procedure to do this all was well. The car is like I've never felt. The throttle response is at an all new level. The intakes along with the throttle body mod I believe work very synergistically. The car feels like it wants to jump out of the paint/skin. I swear P400 feels like P500. I am extremely HAPPY. Did not dyno due to lack of time but future plans will be to work the heads and then it will be done. Hope for substancial gains. Will keep informed.