Factory Five Roadsters
I ordered my rear IRS from Mike Forte https://cobradreams.com/2019/12/11/ordered-the-irs-center-and-knuckles-today/ and it had to be drained since it wasn't on a pallet...
I know many of you have installed the IRS, and I don't want to start a holy war - but I've seen tons of info on Amsoil...