I can not comment on the product or the vendor. I did not read the add to see how you would attach a 5 channel amp.
Can you fit it in the dash yes. I had to fabricate new front mounts. From memory and the pictures it seems the black mount pin had to be removed or the dash drilled for it.
The best feature is the EQ and the steering wheel control.
The two minor issues are a red digital display(on mine) and the bulb that lights the display is $20, Yes one bulb $20. I replaced the bulb with a red led(NOT plug and Play). As I no longer have a blue digital speedometer the radio display does not seem as out of place. Before you ask the LCD display has a red filter built in to it, and I do not think it can be changed.
I modified mine for direct audio input and I think these radios are better than stock. Local radio stations add base or mess with the EQ so the EQ gets a lot of use.