can i still use my factory casing with an aftermaket head unit?? or do i have to use an aftermarket casing?? it's for a teg.

 

I'm not quite sure I know what you mean by "casing". If you are referring to the metal mounting sleeve that your radio chassis slides into, then no. They are manufacturer specific and sometimes even model specific within the manufacturer. You may be able to use one that is not designed for your radio but I doubt it would lock the radio chassis in place like they are supposed to.

Hope I'm referring to what you're talking about.