I don't have a comparison between this modification and standard one, but 2 years ago I was doing pre production tests for VMC and I compared another Crono modified kit with standard kit. That kit was a little more aggressive however on a modified lml crankcase, reed valve, phbe36 and big box I gained more than 4HP and 1000revs. Clearly I lose something at low revs but who cares?
Crono is not a plug and play kit at all, and in fact VMC now sells also Crono without nikasil coating so that you can work on ports and after you do the coating.
For p&p stelvio is much better