I usually drive the Roadster, so i checked out my times i had of the Cup and Roadster on Laguna Seca.
1.44.404 in Race for the Roadster
And
1:42.999 in Race for the Cup version
So your 1.50 pretty much says it all.
You haven´t practiced enough, it took me two seconds to find this out starting with the last turn and out on your fastest lap.
Last turn before straight: Well i say you took that corner at about 25% of what´s possible. You basically glide through the turn, upshifted very lazy, got on the gas even lazier,
Turn 1: You should be able to get on the brakes when you are on top one of the white lines. You braked several meters before that, then glided down to the turn and here is where i stopped watching
Do 50 laps and come back to us m8. This is probably as contructive as i can be so practice, practice and practice, then show us your improvement