I was watching some old 0 to 100kph runs with my stock turbo today and it came on much quicker than it currently does.
I've noticed that going from the stock cast wheel in a stock housing to a gtx wheel in a non ported .7 housing added spool time and moving up to a gen 2 gtx66mm supercore added more spool time again.
The mid range changed a fair bit each time and the top end only really came alive with the latest turbo.