I agree with the Ecsta at full depth. Works great in light to medium rain, as mentioned also works great on a drying track. Even in the true downpour, they should be fine, in that case visibility is more likely to be the problem, not tire grip.
I run Hoosier Dirt Stockers on my 280Z, which has a locked rear, in the wet. They are like having the car on rails and easily overcome the attempts of the rear axle to break away when power is applied. However they are very temperature sensitive and will quickly destruct if run dry. A real pain if it is showery, but a delight when it settles in to rain for a few hours.
Bill Miskoe