Originally Posted by b15

The probability of issues increases with the the cheaper spacers. They may not be all machined the same, fitment might not be the same for all 4, they may crack, etc. Ichiba is the first that comes to mind. It's the same difference between a $15 Auto Zone rotor and a $65 Brembo Blank. They do the same thing, but you're less likely to have issues with one of them.

Z1 has their spacers on sale starting at $88 for 20mm bolt ons. $33/pair additional surely won't break the bank.