How easy is it to change the air filter on the 1.0 TSI? I'm looking to install a re-useable K&N (like I have on previous cars) and, whilst I've only had a quick look under the bonnet, it looks like you have to completely take apart the air box incl. the breather pipe. Is this right? I'm hoping there's an easier way as the bolts seem to be underneath the box and not very accessible.