Is it any chance it's just the usual new zorst "snap crackle pop" until it carbons up?

The new zorst on the last Subaru used to make all kinds of "rally sounds" until about 6 months after it was installed.

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[COLOR=Black]Liberty GT Spec B tuned 240 HP & 372 Nm at the hubs.[/COLOR] "Instead of banning high performance cars - ban low performance drivers"