Solar panels

So due to the D.C. fridge that seems to come standard in all newer models, I am looking to do my first solar upgrade. I want to be able to get at least 2 - 3 days with semi cloudy days. I am trying to maximize the original set up. I don't want to just throw out good equipment without using it. I have a 10 amp "go power" pwm solar charge controller that also came with an 80 watt panel. I am pricing out 100 watt panels because I've heard my controller is good up to 190 watts. With my add on I will be at 180 watts. I also will add a second 12 volt battery in parallel. As I look at panels, I see not all solar panels are created equal.  I see dozens of 100 watt panels for 100 dollars or less. But I decided to go to the same mfg of the controller (gopower) and they sell a 100 watt add on, no controller or things I don't need, just a panel, mounting hardware, and splicing plugs, to be able to connect the new panel to the old, and no wiring needed. But it costs 412 dollars. Big difference for "the same thing". I assume the "gopower" panel will be way better over all, but does anyone know if it really makes a difference. I still have some time before spring to figure this out, but I'd like to start ordering the parts. I'm pretty sure I can install this myself, but, I am nervous about putting holes in the roof too. Anybody done this?