[IROCZBeast]

I'm sure this is probably a common question but here it goes.

I'm about to do my first oil change since I bought the car. Who ever had the car first wrote down when they did the first three oil changes but then got lazy. The first two are castrol synthetic and the third one is mobil 1. I'm pretty sure when I bought the car the guy had said he was using mobil 1 synthetic.

I was looking to use mobil 1 synthetic now when I do my first oil change, it should be ok right?

I'm just thinking worst case scenario they started with synthetic and got lazy and stopped (which I doubt) would it be bad to go back to synthetic?

Oh and I geuss I should use 5w-30 right?