I am converting to 5 lug using a set of 911 front struts.

It is time to start compiling a parts stash so when everything is cleaned up I am ready to do the install.

My car is set up for autox and have been running Koni on the 4 lug set up, but it is still streetable.

Which Bilstein would be the recommended fit B6 or B8?

Hello, not sure on your ride height, but maybe this helps.
I have B6’s in my (lowered) euro ride height 911 and love them firm ride handles great….will be using B6’s in my 14 as well. I think spring rate, sway bar size, and bushing material may have more of an impact for autox, I am also sure the larger brakes will help lower times on longer courses, maybe not as much on tighter ones. I am sure there a few guys that autox, and have more experience will chime in….