pcv and thermostats for street strip cars ?

Heat is energy, that's a fact. However if you are leaving it in the engine it's wasted and it just dilutes the incoming air fuel charge. Colder air is denser air, The denser it is the more oxygen is in the air. The more oxygen you can get into the cylinders the more power it will make with proper jetting.

The reason the OEMs run 195 thermostats is for fuel efficiency and emissions, not for maximum power.