there are 4 variations of the 4agze ,, early ones had a lower comp ratio and a bigger port head with no oil squirters under the pistons ,, later engines had higher comp ratio , smaller port head and oil squirters under the pistons ,,, All had a forged and ceramic coated pistons as std ,, if the engine is not low on compression i wouldn`t bother rebuilding the engine as they are a very strong engine in std form .. they are 25kgs lighter that a CA18det ,, i have some custom madrel bent extractors to fit a 4agze into a 1200 4 sale ..