i've had to bore my a15 too 79mm which i believe is maximum i was just wondering what pistons could now be used as standard units dont go that big

Did you actually bore the engine without having pistons for it first?

Most people seem to use Mazda pistons & I think that the MX5 engine is the preferred donor. Hopefully others will either confirm, or set the record straight.

well no i havent acually bored it yet but i will be and the info i found was subaru justy pistons but i'll look into the mazda ones, thanks.

mazda e5 pistons will fit with some mods like machine small ends but the biggest problem is head gasket size. One other thing, the larger the bore size the thiner the bore which can pose problem in big horsepower engines.