[Cabdriver]

I would go check for a boost leak somewhere. The exhaust tone changed due to your wastegates bypassing the exhaust flow. Turbos are bypassed for a number of reasons but this can happen with a leak without a MIL.
Exhaust would have nothing to do with this condition. What type of intake mods do you have? I would start with chargepipe to throttle body then diverters and work my way down from there.