The helmholtz resonators really need to be closer to the downpipes on a tt (closer to front headers NA) to be more effective.
What really cut the sound down was either keeping the 2 OEM main cats or in my case installing aftermarket cats in the exhaust. Reallt cuts 1 noise and drone and 2 srinky idling exhaust. Its a win win IMO and worth the loss of 5-10hp. Lol