Hello. I have a 2003 Toyota MR2 that I purchased with 144k miles. It runs great. I've changed the oil once with I believe Pennzoil conventional. It is my daily driver, but I do go WOT occasionally, and take it to autocross. I live in Orlando Florida, so it does get hot here. I've been looking to put decent oil in it, but with the higher mileage I'm not sure. Should I start with synthetic? Like maybe Pennzoil Platinum? Or stick with conventional, like Castrol GTX?