The CSP front discs are zero offset or very close. I had the solid rotor ones. I'd get the vented if i did it again.
The Ball Joint drum spindle, 4 piston Willwood Airkewld are NOT zero offset. In fact, it's about 3/4" per side, or 1.5" total. Not a problem now, as my new car has a 2" narrowed beam, but definitely a factor. Also, the machining for the grease cap and seals is not correct as I received them. Off to my buddy's lathe to correct.
My rears are Airkewld as well, but use a nice tig-welded caliper mount and a VW Golf single piston caliper with ebrake. Also have steel braided hoses and their MC that comes with the kit. The rears are zero offset. And the cool thing is bolt patterns are interchangeable, as long as they are 5 lug. American, 130mm, and 205mm are available. I got wide 5, with 14mm pressed studs. 911 ball seat lug nuts work fine.
Now, despite the high cost and the extra work I had to do, they are worth the cost. They plain old work. I beat on them for two hours, playing high speed tag with an old Alfa, an old E type, and a Dino GTS.
No fade, ever. No warping. Just excellent late-braking, time and time again. From 80-90 down to 30-40, over and over and over. Complete confidence, every time. Now that is an endorsement!
I would stay away from EMPI brakes, they are cheap and HEAVY, especially in Wide5.