I use regular Castrol GTX 10w30 in my turbo honda, mainly because it's cheap and I change my oil every 1000-1500 miles. I also don't really drive it that often anymore, so getting synthetic oil would just be a waste for me. If I had a built motor or expensive ball bearing turbo, then I would run synthetic, but not with a sotck d-series motor and $300 turbo. My dad uses synthetic in his 06 SSR though (LS2 engine).