I just got a 2006 drz400S. It has stock jetting, but someone has drilled 3 one inch holes in the top of the air box and installed some unifilter air box vents. I am thinking about doing to 3x3 mod and getting a JD kit, but it seems that with the orignal snorkel and 3 vents, it may have about 6 square inches or so of opening already. Any advice? Should a do a smaller square hole and shoot for a total of 9 square inches. I live in CO, bike will probably never be below 4000 feet. Thanks.