Bangkok motorbike garage

[Shark]

Hey Guys,

I'm looking for a garage in Bangkok (as I'll most-likely end up there 2-3 days a week, it sucks I know), one would say there are many of those.
I'm looking at buying a used Rebel 300 (2017) and afterwards customizing the heck out of it. This obviously due to legal reasons needs to be done by a Thai.

I would be a 2017 model and afterwards upgrade the light to led and change the clutch and break handle as minimum and perhaps I go way crazier.

So the question for all of you driving a motorbike out there is which garages are trustworthy.

Thanks a ton,

Shark