Under normal conditions you can use regular oil if you change it every 3000 mi. If you change at the recommended 3K mi than the oil has not broken down. It would be a waste of money to put synthetic. Now if your always getting on it or Racing than you can brake down the oil at 3Kmi probably. But a lot of people put it in cuz it makes them feel better. And another reason to use synthetic is if you are lazy and don’t change your oil and go over the 5K mi. also I would also use it if your car runs over the normal temp.

 

I cant imagine Synthetic being bad for any performance engine. Thats odd.

 

My suggestion is to do a SEARCH. There are many threads on this topic.