Stop worrying about the class of oil. API SP is latest technology oil and its way superior than SJ, SL or SM. I have been using zic 10w40 fully synthetic API SP since 1.5 years now in my suzuki cultus euro 2 2013 model. My car is running better than ever. All you need to worry about is grade. Some people are using 5w30 also and they have no issues. But since I am using 10w40 since the beginning, i am skeptical about shifting to 5w30.