First of all, you are nuts if you are driving 100mph on a public road...

To build boost, the engine has to be under a load, even at 5500 rpm, if you are in fact cruising at that engine speed, the engine should be at almost full vacuum, not boost..regardless of the spooling rpm of the turbo.

The spooling rpm of that turbo will be determined by AR and trim, saying it's a T3 hybrid is not enough information.

good luck with the setup..it's all in the tuning, make sure you also run cooler plugs..and keep those speeds down for your own sake and for the sake of other drivers...