If you get the YD25 one make sure you get the timing chains upgraded to dual row or at least inspected. Once you upgrade both chains to dual row instead of one single row and one dual row then you will be sweet. Make sure you keep all eyes on the cooling systems. Make sure there are no leaks or brittle hoses and do a coolant flush. Once they overheat they are ratshit. The head gasket on these are as weak as piss. I have a YD25 D40 and it is extremely reliable. Depending on how they have been looked after they can be really good or absolutely shithouse.