You bought a sports car, spend thousands on mods, spend thousands on fuel and insurance and you wouldn't spend a little extra for your safety in winter? In my opinion if you want to use it during winter you just buy a set of winter tyres, period. Winter tyres will last many years and will make a significant difference in low temp and snow. Even if there is no snow, in low temp summer tyres will not perform well.
In slippery conditions or fresh snow you have no chance to get away with TC on and 1st gear in a 300 bhp rear wheel car... With the TC off the LSD should also help a little by not allowing one wheel to spin while the other stands still.