Is it just to press new bearings in or do they have to be machined
afterwords (reamed)?
Depends on the brand and sometimes the particular bearings. I got some that needed to be bored that most people have been able to use as is.
i believe glyco need to be reamed, but clevite do not. always best to check though. manufacturers should have them labeled as such... i ran into just this sort of problem with my mTDI... in the end the glyco got wrecked, and clevite's were put in.