http://www.andyforrestperformance.co.uk/26032.html
The link may be useful.
Most people will say an oiled filter is not a good idea due to the potential to fudge the maf and in turn your engine. Some people have used them for years with no issue so.....
Theres no performance benefit Ive ever seen for an oiled cotton filter e.g. K&N over a dry filter e.g. Cosworth, STI, Ramair etc, so for me its a no brainer.