A Revo Muffler Delete replaces a component of the intake pipe designed to quiet down the noise of the engine on boost at the expense of performance. By replacing this muffler with a straight through pipe, you get enhanced induction noise and reduced boost lag.
The Revo Muffler Delete is made for 1.8 and 2.0T engines. Standard OEM components are designed with a slit in the muffler pipe to disperse the air and silence the noise from the turbo. A side effect of this design is the hole creates turbulent air in the pipe which can also decrease engine power and increase turbo lag which is not a problem for a non-motor performance enthusiast.
For the motoring enthusiast however, this is a pointless trade-off. Losing power and noise is the worst of both worlds.
The clever design of the Revo Turbo Muffler Delete counteracts this, ensuring the muffler pipe is made from one piece of solid pipe and completely sealed; increasing airflow by decreasing the turbulent air created by the hole. The smooth flowing air then results in improved drivability and decreased turbo lag.