I've been running synthetic oils for years - I've seen and heard enough positive results to warrant their additional costs. I use to go 5K miles before changes. I just switched to Amsoil this year and will be doing once per year oil changes with filter changes every 6 months. What's required is a very good quality oil filter (no Fram or generic stuff. I'm using the new Bosch filters, but other HQ filters like Mobile1 and of course Amsoil will work as well). Wish I had 250K miles to give actual long term use feedback, but that will take me a couple of more months
Cheers
