Hopefully not too much above 150 kts as the Vne is 155!
This is quite a normal speed for a/c such as the 76 and Dauphin, though when at max weight they tend to fly nearer 140 kts.
It would be IAS, not TAS; you would not normally have a TAS indication other than on one of the FMS/GPS pages (though if the wind is displayed on the ND you can get a pretty good idea from the ground speed).
What is more impressive with the EC-155 is that you can maintain max cruise power at all altitudes and not become Vne limited, whereas the 76 has quite a penalty as you climb. Consequently you can see IAS' of 140 kts at FL80-100, giving higher TAS than sea level but with a 20% reduction in fuel consumption.