AO Platinum Member
Join Date: Aug 2003
Location: London, England
No downsides and yes the JTD/2.5v6 pipe will also fit, which is what I have on mine and was the normal mod until the GTA came out. Unlikely to gain much by using the GTA version instead of the JTD/2.5v6 on a TS though.
And to be clear, you don't replace the original intake system, it is just removing the resonator chamber and fitting a JTD/2.5v6/GTA pipe in its place. Some markets outside Europe didn't have the resonator anyway and used a longer version of the pipe instead.