Installing aftermarket stereo

[Oyagi]

Sorry for this totally newb question.

I am not an audiophile, I am a performance guy. But...my oem stereo is finally calling it quits so I need to replace it.

I tried to search but there just too much damn info, so if anyone can point me in the right direction I truly appreciate it.

I want to install an in dash single DIN motorized dvd system, but retian my oem speakers. Is this doable?

I also saw the thread by Tamoske for the CF dash. Are there other options for mounting non-oem stereos units?

Also, where is the grommet on the front and rear firewalls?

Thanks
John