By this logic you should have to go for a cert if you take your wheels off or put new brake pads in. Which the LVVTA once actually insinuated in a particularly dented Facebook post about brake rotors needing to be certed in case you installed the wrong size ones (???).
Honestly they do my f***ing head in and I hope they read this, yes without them it would be very very hard (actually I don't know, would it?) to modify cars and they provide a framework for us to do that, but some times it's completely cooked.
Literally from the NZ Car Construction Manual:
And it's just bulls***, over the years they've had some spectacularly useless rules that have taken years to peel back and cost modifiers thousands of dollars to comply with stupid requirements that, if someone engaged their brain for about 20 minutes, wouldn't have made it past the draft stage. When was the last time you heard of a driveshaft hoop that did f*** all on a modified JDM car with less than about 800hp?
The entire organisation was built around the concept of bearded hotrodders (who are wonderful, btw) stick welding bits of car together in their shed, not the "modern" version of car modding which is basically Lego except larger, dirtier, and generally undertaken by people with lower IQs.
EDIT: Apologies OP for derailing your thread. I guess the sparknotes is "be prepared for some bizarre obscure cert requirement".