i got another couple of pistons from a boy up the country same make KS but from a later 325i (post facelift i think)
thought they were the same until i was cleaning them tonight and i've noticed a difference in the valve cut outs my original pistons have a noticably deeper cut out for the valves

dimensionally they seem fairly similiar and weight ways they would probably all balance up
would there be any issue with me using one or two different pistons is their a difference in compression ratio? what effect would this have?
any thoughts would be greatly appreciated
Willy