That all depends on who did the porting and and what style of port job you have. I have herd fast, hjr, wild card all say that their dune port cannot be reported for a 4 mill because the the transfer ports are opeaned up to far. If you have a clean up port job then yea you probably can get away with it. I am sure there are shops that claim to know what they are talking about, that say they can just to make a buck. Look at it this way; You have one shop saying you need to start over with new cylinders, the other shop says they can report them with no problems. Wich one are you going to chose? Your banshee will still run, it just wont have the power that it could.
josh