Just measured the cylinder bores, they are 81.035mm, so they are no good, except for big bore core exchange
in prinzipal i would contradict
the standard piston size from factory is, following the manuals from gen1 & 2, at both 81 mm,
what means the real bore size is around 81.03 - 81.04 mm
so that your measure is still in specs.
but the dark dot on the pic makes me suspicious - in my view a bad sign - and causes by that the cyl. should be bigbored to 1st oversize (or replaced by "new").
but that 1st over would be very expensive - i guess ~ 1500 € at minimum
cyl. drilling + honing 1 over ~ 250-400€
nikasil re-coating ~ 400-600€
piston set 1st over ~ 600€
ring set 1st over ~ 300€
a good, preowned, block incl. pistons (with no bad marks, etc.) should cost for gen1 around 350-500 bucks
plus a set of new standard piston rings ~ 280€
then youre at ~ 600-800€
allways plus gaskets etc.
a usual block / piston set should last, thank to the nikasil coating, for way over 200 000 km
provided that the engine has always been warmed up well, has always experienced good oil change intervals and has not been constantly driven at very high to maximum rpms .
the rings eventually should be replaced after 20 years and more of being pressed in the cyl.
they may lost some springforce
what can cause a lost of compression and a increased oil consumption .