S13 coilover lower bushings are not universal

This should be obvious by now, but every coilover is different, and expecting adapters to universally work without some fiddling is foolish.

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The adapter bushings I produced are longer than they have to be, both the narrower shank, and the larger head, which means they require trimming, but they give you the freedom of deciding which side needs to be trimmed (or both) to suit your brand of coilover:

s13-bushing-trimmed.jpg

Note what happens when we try the Stance adapter bushings on non-HSD-derived coilovers, (same design sold by ASCO and Powertrix):

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As we see, that's not going to work, but that stepped diameter on the head is to be more compatible with the Z31 lower mounting bracket, which has 4 protrusions to help center the shock bushing…

Since my adapters are not split side to side, there's no provision for those bumps, get rid of them (I hammered them flat initially as best I could, then used a dremel with a diamond bit to smooth them down fully):

s13-bushing-diagram.jpg

So there's no one-size-fits-all, and it's fully possible you need an M20 washer to take up any space left on the narrow end of the bushing adapter if the coilover sleeve is still too short, but that's easy enough to add.