Shudder / vibration Audi Allroad when accelerating hard

A 2002 Audi Allroad with 80,000 miles recently began to vibrate in the steering wheel and stick shift when accelerating hard. The higher the altitude, the harder the acceleration, the more vibration. I first noticed this above 8000 feet.



The shuddering began after a new RS4 clutch was installed and the multiple hoses between the two turbo bypass valves and the intake throttle body were replaced with a one piece pipe.



This car has a modfied ECU and third party high perfromance turbo bypass valves. In addtion the tires are brand new M3s (I have run M3s on this car for the last 4 years.)



One shop stated that they had a simiiar problem wiht a Cayenne and the trouble was a flutter in the bypass valves.



Any suggestions?



Thanks



Are the mods actually been sent to a tuner or just installed? Any major changes on a turbo car require a tuner to typically fine tune engine management(program) to work with specific setup. Typically your car is placed on a dynometer and run in various manners to make sure tuning is correct.