Gauss:

The question is B4T or B6T? I assume the latter.

or a (far-fetched) muted N/A with particle filter?

Yep, that is the sound of those 2nd batch GT3 RS with filter....

Smiley


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2017 991.2 Carrera 4 GTS | GT Silver Metallic - The GT3 Killah!
2013 Audi S3 | Glacier White