i tried the K&N panel filter in my 1.8TD mondeo and it made no difference at all, apart from it made the MPG worse.

most mechanics i have ever spoke to advise against induction kits, but dont listen to them!

i then got the K&N 57i kit and i could feel a difference to power, but then realised i had spent £110 on a tiny cone filter, piece of bracket and a crappy air scoop to screw underneath.

so i sold it and fitted a decent sized cone filter, heat shield and made my own cold air feeds - and then it worked very well indeed.

forced induction engines prefer open air filters IMO, but do need plenty of cold air feeds (ideally relocate the battery for more space and breathing).

other stuff to do which works well on TD's is decat, bigger intercooler, and chip/tuning box/remap