I would be a liar if I said I hadn't taken a flap disk to brake calipers before to take off more than that. That's so minimal, assuming the wheels are torqued properly and didn't just bottom out on a spoke.

I'd skip the spacers, and sand back the caliper juuuust a little bit. Looking at the wheel specs, they're quite heavy more like a typical cast OEM wheel than any performance wheel, which could explain the super thick spokes. Being that they're also flow formed, the spokes are way beefier than they need to be unless you're going to use them on a truck. I'm not saying to grind them back, but more than I'd be incredibly comfortable with them having touched the caliper like that

 

Amazon.com: Customadeonly 5x114.3 Wheel Spacers for Mazda 3 6 CX-9 MX-5 G70 Tucson Elantra Veloster Forte Optima (3mm Thick 2pcs) Hubcentric 67.1 to 73.1 -Works with Aftmarket Wheels w/ 73.1mm Bore ONLY : Automotive I did go ahead and order these spacers, at least these have the hub rings built in. Personally I agree that there's definitely enough meat on the caliper that it shouldn't cause any serious damage but between the cost of the calipers and the powder coating better safe than sorry.

 

It already needs to be re-coated, so I wouldn't feel bad taking a lick off of it with a flap disk. Having lived with spacers on my TT for some years, I'd be happy to not ever do that again hahaha

That aside, don't try to run evo x calipers on those wheels as they won't even be remotely close to working.

 

I ran 25mm spacers on the stock wheels for a while so I'm not afraid of 3mm lol. I will say the absolute nightmare of sanding the powdercoat off the caliper halves' mating surfaces, the pad shim surfaces, and cleaning it out of every threaded hole in them, not to mention the residual particulates left inside the calipers, has turned me away from having them recoated. So I'll take the spacers in this instance, good to know about the Evo X calipers though, for anybody else who might consider this setup.