I dont know how you intend to do this extra ducting the SMIC on an
ibiza, as its already really close the front of the bumper on the side, with vents through so theres not much more which can be done, and especially nothing which will have any effect. Like Mike says, the only real way to make a difference is to put a FMIC on, but again only if you have a harsh map and bigger turbo will you be pushing the SMIC.