CincinnatiFiero wrote: could I space the caliper carrier 3mm
Absolutely! That's an awesome find on that rotor! Everything lines up except the height.
I don't know if its safe to use the height of the floating rotor as a reference, since the disc could technically be anywhere in relation to the caliper, opposed to solid rotors. But there's also a flipside to that. Your car has caliper carriers that allow the caliper to float forward and backward in relation to the rotor! Is it possible that the carriers have enough variance built in to allow the caliper to slide back an additional 3.5mm? I would definitely try that as an option first before spacing the carrier or disc.
If the above doesn't work, you have two options.
1. Put a 3.5 mm spacer behind the rotor. This will push your wheel out an additional 3.5mm. You'll need long enough wheel studs.
2. You weld a 3.5mm washer the back of the aluminum knuckle and machine the face the same amount.
I did a little googling and found that the w210 E430 uses the exact same knuckle as the E55. You could pick up a used set of knuckles cheaply and have them machined, given there's many more E430's in yards than AMG's.
Here's the left knuckle for a car without 4matic:
P/N: 2103300020
The caliper mounting tabs are at 9 and 7 o'clock. Looks like the face is raised enough to be able to take 3.5mm off without going into the base material, which would promote stress fracture in aluminum (If that's what it is. The oem parts appear gray like aluminum, so I figured the aftermarket stuff is Al with black paint. If it's steel that's even better for machining). But if the carriers allow for you to use the oem setup without any machining, I'd definitely go that route and keep it simple.
Losing the directional rotor vanes will be a loss in high temperature braking. But from what I've read, your car already has class leading braking power, so a little off the top won't be that much of a loss. I'd go with Will's advice and use high quality or OEM SL500 rotors vs aftermarket.
Edit: Just thought of something. The new rotor might need a concentric ring or machine work to fit onto the hub.