I have abut 1500 miles on my 4 cyl Sport and have always used Castrol GTX oil but I have thought of trying something different in the RAV. I have followed the post on synthetic oils and so far I am not convinced I need them. My Driving during the week consists of shot trips to work of 2 miles and some road trips on the weekends. It does not get to hot or cold in Georgia normaly. Any thoughts?