When I built my 30 I discovered that the 25 head came with a different coolant temp sensor than the 20/26 (my 20 one was yellow, broke it, put the brown one in from the 25, ran in cold start all the time so nabbed a yellow sensor off a 26 and worked fine), now I don't know if this is a 20/26 & 25 thing, or an R32/R33 thing..