Best air filter for clio williams?

I'm thinking of upgrading the airfilter in my Williams 3 and was wondering if anyone knows what is the best one to get? I'm more interested in making it sound better ("throatier" I think!). Any suggestions? I'm in the UK, so a UK supplier would be best! :)

cheers!

i have been told a piperx filter is the best bet for a throaty sound