I've been using BG 44K in my cars for years and have loved the returns. Ford Expedition, Nissan Maxima, 05 Outback 2.5i and 05 GT all told over the last 8 years or so. It is pricey, but I run it every 20-25k miles and I see a 1-2mpg drop when it's time to throw it in again. It's not as hard to find as it once was either.