Did a search.. not much info. I've been using AMSOIL products in my cars, trucks and bikes for years. However, looking at their website I don't see where they offer a 0-40 weight oil, however they do offer a 5-40 weight oil.

I'm in eastern NC, where it's been in the high 90s for what seems like weeks.. no joke. Safe for use?

 

I've used Amsoil for a while myself and have had great luck with it. I checked and believe that the 5-40 is approved and would work just fine but you might want to contact Amsoil to be sure.

 

Last Porsche Brand approval list I saw Amsoil was not on it...neither was Royal Purple which is another really good oil. I've used both before in a race boat with a 502ci engine and they performance well.

 

^ I've used both of these oils in my S2000 (with a 9300 rpm redline). They are fantastic oils.

Not sure if the 5W-40 would really matter in the summer. If you lived in a cold winter area that might make a difference on startup only. I don't think I would sweat it.

However, a good website to research oil and its characteristics/properties is the LN Engineering webiste.