The only large connector on the right side would be for the Monsoon amp. You can check by comparing it to the diagram and pin-out in the Monsoon FAQ sticky at the top of the section.
And don't worry about being told that the Monsoon amp sucks. Some people just repeat what they've heard without really knowing. The Monsoon system gets a bad reputation because the head units are just ordinary Delco radios that produce lots of distortion and the speakers are made of cheap materials (although they don't sound too bad until they blow). You can get a replacement Monsoon amp fairly cheap and it will produce clean amplification into eight channels provided it gets a clean input signal. If all your wiring is intact, it is an option you might want to consider.
White 2000 Trans Am (sold)
White 2011 Mustang Convertible
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