IF the problem is the same as mine, (intermittent, sporadic engine surging causing the car to "porpoise" then tell them to speak to cadillac technical support and open a technical assistance case. the engineers will tell them what to do witout demonstrating the problem. for my repair, as listed in the beginning of this thread, the repair servicing dealer never did a test drive before doing the repair.
If your problem is not the same as mine, but rather just a hesitation on acceleration, maybe you should see if you can make a small drive in another blackwing? who knows, maybe your problem is just a characteristic of this engine? it is not the smoothest engine? not trying to dismiss your concerns.
for the brake problem, on my previous V, one of the brake pads was sticking, so one front caliper was only using one brake pad. this made it seem like braking was more on one side than the other. the pads can sightly rust and stick to the caliper body rarely