I'm not saying that the dealer does'nt recommend it. I'm just saying that 5W oil is for a broader temperature range for people like you who live in cold weather climates. If you live in Texas, Florida, etc. and the tempertures reach 110 degrees in the summer then you don't want to be using 5W oil on track day. Trust me. I have asked my friend in th eoil business for a more specific explanation and I will post it when he responds.