Re: Homeowner light duty 3/8 impacts
Sunex is used professionally by many, top notch product. I have some Neiko XZN bits I use mostly for VW brake caliper brackets, and they work well.
As others said, with the output levels of most 3/8 impacts, especially with what I'd call "homeowner" levels of air power, most anything should work. I always focus on complete sizes with no skips over and above all. Yes, your asian car may not have factory 18mm bolts. But the aftermarket balljoint or tie-rod nut you install may.