What exactly is taking so long? A modern EFIS screen will have carried out it's IBIT and come on line within 30 seconds or so, the AHRS about the same time on a stable platform, and the FMS maybe a minute. Where does the 2-3 minutes come from, and are you REALLY wanting to be airborne in less than 2 minutes after engine start??
Of course, in an S-92 you use the APU to get everything on line
