I have a ca18det in my wagon and have been in a sr20det sedan and much prefer the sr by a long shot but in qld its not allowed to do a sr in a 1200 so i had to make do with the ca. In my personal experience with my ca which has had every single part replaced with brand new parts a ca is quite reliable on 16.8psi and so much fun BUT i have had a head gasket go on me and yes with new head bolts and re tensioned ect but the one thing a ca does not like is HEAT !!!! once the engine has a little too much heat in it the head needs to come off and be re surfaced.. Apart from that the engine i have in the wagon has been un touched for two and a half years and it does get a work out with all the monaro's in town !! not that they are much of a challenge for the old girl !! ha ha ha ha