I have two sets of tires for the minivan right now; HPI Super Radials on HPI Split Six wheels for dry weather, and Team Schumacher Shimizu rain tire premounts for wet weather. The Shimizu tires are impressively sticky; they grip wet pavement about as well as the Super Radials grip dry pavement. I suspect they might do well in the winter too, when it's freezing-cold and the super-soft rubber firms up a bit.
At the speeds you're going, I'd recommend the V-Groove tires or the RiDE USGT tires. They have better grip. I have the V-Grooves on all of my 40mph+ cars, except for my RS4 M3 rally car which uses Pirelli Rally tires (and rarely hits 40mph, and has a gyro to help it at high speed), and my RS4 Viper which uses vintage X-Pattern belted tires.