zipper, you do not have to cut away the air box to add cams. From all I read air box removal has little benefit with EFI. I have left my air box intact, just pulled the snorkel and installed a Uni filter. Had 904 big bore and cams done at the 12K mile service. The cams really woke the motor up. Originally the power just died above 6000 RPM. 5000 to rev limiter is much stronger now! Never hit the rev limiter before those mods. Cams and a proper tune / remap will make a big change in performance.
