when i install my new door speakers I need to use some speaker gasket to seal the speaker . Do you suggest going to an audio shop and getting the gasket specifically for speakers, or just use something like weatherstripping?

I think you would be better off doing it right the first time. Just go to an audio shop of your choice and buy the actual gasket. I'm pretty sure that it'* not the easiest job to do in the doors and the least time consuming ya know.