Apologies if it's been asked before, I did a search but couldn't find anything.

How strict is the annual inspection when it comes to modification of a motorbike? I know it's incredibly lax with the road-worthiness seeing as how my bike got through it's annual inspection without me realising the brake light doesn't work. Are they as equally lax on mods?

I want to just some basic stuff like stainless steel wrapped exhaust, some lower down handlebars and remove all the decals and stickers.

I paid 520rmb to a bike shop to get the inspection done for me. This is incredibly expensive, is that a "make sure it passes" fee? Is that why it passed with a non-working brake light?