Hey, my s1 is breathing heavy and ive already fitted new rings, been told that the block needs boring out, there`s a guy on here selling s2 +0.5 mahle pistons, would they be ok in my block? He`s also selling a s2 block that has been bored and honed for these pistons, nut been told it won`t fit my head? Is this all true??

Cheers Neil