Terraclean
 

http://www.terraclean.co.uk/pdfs/Subaru%20Test.pdf

Seen the reps at the NEC the other day, anybody had this done. Subaru Canada recomend this a s part of the service schedule. See the link

I've heard of this one too - seems quite a lengthy process but worth it all at the end for emissions etc. Haven't had this done myself but a mate of mine with a Mondeo ST220 had it done and he said he felt the power gains etc :)

Supposedly as part of the process, they do hump the sh*t out of the engine