There is people using the car dealer services although some could be cost (un)wise. And some use Tayseer services. There are a couple more places (always nearby Petrol Stations) to perform these changes/arrangements. Bt to be honest never been to Industrial Area for such endeavour.

For customizations you MUST get a permit from the Traffic Police (at least that is what I have been told) and with proper justification; otherwise forget about it.

Regards!!