I just bought some pipe off ebay, 76mm diameter, about a foot long with a 45 degree bend. I have made use of the standard airfeed pipe, I'm thinking of getting a length of flexible pipe though coming from behind the front bumper or something. The original plan was to move the radiator over slightly and have the filter sat right behind the bumper, but considering some of the puddles I've been through I'm glad I didn't. Heat soak hasn't been a problem. One thing I have noticed though is there is a very slight flatspot somewhere in the mid-low of the rev range, but for this is more than made up for by a high end gain, once you get to 4k rpm it fucking takes off lol. Aslong as the airfeed pipe isn't too long then a BMC CDA would probably be better. I just went for the cheap option I spent about £50 altogether, not bad for an air filter, pipe, and silicone reducer.