Yeah, been there done that. Shenandoah is like 5 hours from me, but I have decided to not do it in the 370 because it is so bad on the car and it honestly gives me a headache since you don't get much time to relax.
Here is my lap in the downpour
350Z Shenandoah Wet Chasing BMW - YouTube
I don't mind driving in the rain, but I always question my judgement after each session