confused about a rebuilt engine

Hello Everyone,

I am looking at a car which has a rebuilt engine (not a mercedes) and the invoice on the rebuilt engine says:

"The above named customer requested, understands and accepts that the parts and machine work are not of OE specs, the Block, rods, and pistons have been modified to accept non OE brgs and rings."

"Lathe work-recut ring grooves for replacement rings
Machine block and rods for replacement EG
Remove and replace cylinger sleeves
make cylinder sleeve
grind crankshaft
crack repair basic valve job and surface
fit rings to cylinder
assemble crank and pistons to block"


What does all this mean? Should i expect problems in the future like oil consumption, overheating, increased fuel use, or what? WIll obtaining replacement parts be difficult or what? Thanks...