@Victorious sounds like a great first day with the Speedster! If you could shoot a few videos of the acceleration through the gears and also the tach showing RPM’s at 65-75mph on the highway in 4th gear that would be very much appreciated. Also how’s the gap between 3rd gear and 4th? Does the 1915 have enough grunt to pull or is there a gap there like others have commented? I am thinking with the VMC’s pretty stout 1915 (with 110hp) she likely pulls along fine.
As for the wander, are you sure if was just not ruts in the highway from heavy vehicles and trucks? Some small cars with narrow tires will do that, especially given how little the 356 weighs.