if its too hot it will result in power loss and not power gain. make sure if u go for a cone filter to get some cold air feeds with it. the k&n 57i comes with 2 cold air feeds and is about £90. i brought the viper to start with for £200 and the lack of cold air feeds resulted in power loss. made a bloody good noise tho. im booked in a pumaspeed 2morra to get the full miltek system and to have my viper replaced with the k&n. also gettin sports cat and the magnecor leads aswell. should be a nice expensive day lol. at the end tho should be about +25 bhp.