Recently experiencing a lagging in turbo and hearing a rattling underneath the car. Took it to Audi dealership to run diagnostic ($150.00). Result came back as wastegate malfunction and said needs replaced. Dealership estimate is $981.00 plus tax including labor. Is this a reasonable cost for this repair? Thank you!

Intermittent problem generally first thing in the morning. Engine is running rough and car shakes all over. Engine appears to be flooded. Black smoke and strong smell of unburnt fuel out of exhaust emmission. Switch engine off and restart seems t clear the problem. Could it be faulty ejectors/ignition coil or faulty Catalytical converter