Well you can start by looking at official channels first:
www.ralliart.com (Then click on the world of ralliart). You'll find a map (with hyperlinks) to Ralliart representatives. From there you can go on. In the UK (via official website) if you click on Parts you will automatically be linked to co-ordsport.
You can also go to the website of the Swedish EVO club. (I'm sure the link is on LancerZ website).
Nico