Discovery 1 3.5 EFI exhaust to 3.9

Hi all, I’d like to introduce myself as I’m new to this place. I’m the happy new owner of a ‘90 Discovery 1 3.5 V8i which is in need of some work. The exhaust is one of the things on my list and I can’t seem to find a nice stainless steel set. What I can find is a 3.9 set for a Discovery 1 which, on the photos doesn’t seem to be very different from what I have right now. Does anyone have any experience with the differences 3.5/3.9?

Best regards Geert