Actually - what about the wheel bearings? Not just the possibility of bad bearings, but what if they were not reinstalled correctly with the proper torque procedure?

Not sure where you had your brakes done last, but I dont think every brake shop has one of our special lock nut sockets. It's often more likely that these are under-torqued without the proper socket. but if someone torqued it and forgot to back it off per the FSM, this could lead to increased friction load. And also premature bearing failure I'm sure.

I think either you're lacking power (compression, fuel, spark or air delivery issue), or you have the power and something is acting against the motor - be it the exhaust/CAT issue you chased already, or excessive drag on the drivetrain.

You're sure you're not stuck in 4wd?

Jim