Joined: Mar 2017
Location: Philadelphia Metro Area
Rockauto has the OEM Brembo calipers BR3Z-2B121-B & BR3Z-2B120-B for $207 and $225 each. Only one side requires a $50 core charge.
Therefore, for genuine Brembo calipers the cost is $482. Parts from Tasca are about about $85 more
Your O'Reilly versions with paint and decals (partial cost of decals) = $327
That's a savings of $154 but doesn't quantify the time and effort to paint the calipers.
Is $154 worth it? You may get away with it on the street, but if you ever want to take it to a road course don't expect the aluminum alloy used in the knockoffs will be as good as the Brembo's. I'm sure O'Reilly/Cardone/Autozone didn't test it on a track to see if it will withstand flexing and high heat when stopping a 3700 lb Mustang from 120+ mph on a repetitive basis.
My opinion is that these are just ticking time bombs.