I have a 95 Miata that I drive all year round in Wisconsin. I've been using Pennzoil 5w30 High Mileage for most of my ownership, and a Fram or Bosch filter; whatever is on sale at Autozone. The car has 132XXX miles on it, I'm curious to know if going to a 0w20 or 0w30 would be a good decision to run during the winter months. The 0w20 seems to be easier find compared to the 0w30 around here.