If an engine is a group n rebuild does it differ from standard at all?

 

It could be running to the favourable edge of factory tolerances, ie "blueprinted".

It could have been thrashed mercilessly around rally stages.

It could be a marketing tag to try and get you to buy it.

Not very useful as a description then I am afraid.

 

It belongs to a mate of mine its a version 4 sti he found out it has had a rebuild because of an oil problem so the ends went, and it was sent to a race engine place and was given a group n rebuild so he wondered if they would use standard parts for that?

 

There's no way of telling, other than locating the place that did the work and asking them exactly what their "Group N" rebuild entails. As John says, it could simply be a load of bullsh*t.