fantastic is a relatively mild cleaner is it not? My grandma used to use fantastic on her cadillac all the time to remove bugs and bird bombs and she swore by it. Now, keep in mind my granny is no Autopian. She's from the old school even though she now pimps an escalade on 22's. and yeah it's got swirls.
On a serious note, I absolutely love simple green concentrate dilluted 5:1 or 6:1. I use it on tough interior stains, wheel wells, under the hood and then all over my house. I also use purple power full strength on tires if needed or under the hood sparingly.