After a bit is fishing on the Japanese Denso site I found [url="http://www.denso.co.jp/cgi-bin/plug/4wplug/4wplug-jpn.cgi?name=%A5%A2%A5%EB%A5%C6%A5%C3%A5%C4%A5%A1%A1%D2ALTEZZA%A1%D3&cc=2000&filename=maker5jpn.csv&action=search&Submit=+%B8%A1%BA%F7+"]THIS[/url] selector chart

I have been using IK22's but was considering changing to a hotter plug next time, so will get the IK20's with confidence, that been said i took out one of the plugs recently and it seems to be fine.....

cheers for the info