Engine oil AMSOIL or OEM Subaru

With Amsoil even if it's not signature series I trust it more than any other 0w8.

I run Amsoil and my oil change interval is 25k so the answer is it depends.

I only use Amsoil Signature Series in my B58.

I changed to that and really happy with it so far, shifting is butter smooth.

Based on my own tests, I found the AmsOil to be the best at reducing heat a few degrees. It's not cheap, but it's still cheap insurance, all things considered.

I use Amsoil 20w50 in all 3. You don’t need a different oil for the trans. Amsoil is not cheap but I’ve been using it on my 03 FatBoy since new and have had no problems.

Originally switched to Amsoil for the Noack rating but stayed because it's just good stuff. I now run Amsoil products for all fluids in all vehicles.

I use AMSOIL 5W-30 for both of our vehicles. Never had any issues on either vehicle using AMSOIL.

I just switched over to amsoil and my mpg went down marginally. Also using the PPE larger oil filter 10 micron filter.

personally, I think Amsoil AFL is junk. They ruined a stout oil when they reformulated it to mimick 505.01.