Hi All! My A4 is going in for a Full Service with Audi and they wany Â£59 for a replacement Air Filter. Would it be cheaper/better to get a replacement K&N or similiar brand? Also where is the best place to get one from. I can't find any on the net. Whats best and what kind of benefits are there? If any improve the noise it would be a benefit! Thanks in Advance!