i have a b16 and i wanna change my oil. which oil should i get, synthetic or regular 5w30 and what brand?

 

Any quality 5W-30 will be fine.

If you search a bit, you'll find many, many threads discussing oil.

 

personally i would go with something heavier being that you are in TX. As for synthetic or regular I think it is more a personal preference. on a used motor it's really not going to make a noticeable difference.