Audio mods should always go near the top of the mod list.
Whatever is before a given mod will take priority.
If you have a lot of mods, it is best to separate them by categories.
Even in the actual groups you will need to sub-order your mods.
Example, if you have 5 "sound" mods, they need to be ordered correctly within the group.
Here is my guideline I follow from top to bottom in the mod list for ATS.

( Mods Groups )

( TOP )
- Time
- Weather
- Lighting
- Traffic Density
- Sounds
- Misc. Traffic
- AI Traffic
- Truck Tweaks
- Custom Trucks
- Truck Skins
- Textures
( BOTTOM )

I hope that helps you out.

This is very helpful. Thanks. Where would you put truck physics mods in that order? Would it fall under truck tweaks?

You're welcome, glad it helps you.
Yes, I would put a "Truck Physics" mod at the top of the "Truck Tweaks" section.