Just incase you were not aware,

A alternative to the Rally Foam air filter is the cotton oiled offering by JR/Jetex (same company, JR make the filters but rebranded Jetex for UK market.

Better than the foam IMO, filtration 99% at 2.8 microns with TUV approval, and they have pleats for much more surface area compared to flat foam.

I've used them before on other cars and they are very nice.

Its also cheaper, £37.62 inc VAT:

http://www.jetex.co.uk/website/dropinfilters.php?mak=Daihatsu&id=1&mod=Sirion

and on JR website you can bring up the correct photo:

http://www.jrfilters.com/include/popup_image.php?photo=296&lng=en

http://www.jrfilters.com/filtres/index.php?lng=en

part number same for both JR/Jetex F185172