Yeah I believe it is around the $300 mark, give or take $100. Take it to a shop definitely! And it's fine to replace it at 90k. You CAN do it at 60k, but there is nothing wrong with 90k. I wish this was something I could do too, I just wish I was an all around skilled mechanic, lol. I have 60k more to go before my timing belt change. Good luck with yours!!!