I have 2015 model grande 1.8, yesterday i got stuck in rain water.after i got my car out from water,i started its engine after a few tries.to summarize the engine chamber blew up.Now mechanic says that its better to change complete head assembly than repairing this one.i have visited bilal gunj and found three option that can fit in,most economical is prius 1.8 engine head assembly but it is different than grande in term of tappet cover etc,another in premio 1.8 engine assebly which is same as grande but its double the price.need suggestions what should i do