Nice quality but I have to add my 2 cents worth of info here from having had hundreds of wheels on dozens of cars and used spacers on race cars as well.
This would of saved you money, sorry I did not post this on the forum before.
For such thin spacers DIY or lower cost generic spacers are just fine, they do not have to fit the hub bore perfectly.
As an example. I have use 3mm spacers on the front to clear the coilovers when I run my 15x9 track wheels, I made them out of some high grade sheet aluminum I had on hand, I did not have to make them fit the hub perfectly as not needed but I made them very close as it is how I do things.
Hub centric spacers come into play when the spacer is thick enough to disengage the wheel hub from the axle hub.
There has to be enough depth where the spacer and the ring are strong enough to support the hub of the wheel.
Longer studs are almost always needed.
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I did not see it mentioned, do you have hub rings for the stock hub to new wheel bore?
It is always best to get aluminum hub rings instead of plastic on a car driven very aggressively as plastic ones tend to melt.
Most wheels will need hub rings unless they are made specifically to fit the hub of the car as the load is supposed to be on the hub, not on the lugs.
My spacers were made to very close tolerance as mentioned but was more for giving the best support for the aluminum hub rings I use on my race wheels.
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