Fairly sure OE pistons are not available in 83mm so no idea why he has suggested he is going back to std pistons...
You will need a ring set too and it will have to be a JE set.... rebore to 83mm is normally more expensive as you have to do it in two passes due to the oversize...
Thats not damage by the looks... just skirt contact so 'should' be ok
Ask what the compression ratio is too... if they are 8.5:1 then I wouldn't bother
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