I had grpN mounts installed on a MY11 WRX and didn't notice any increase in NVH under normal driving conditions.
The only increase in noise was when the car was sitting stationary with the A/C turned on, if you are able to increase the min rpm level for A/C running, then you will be ok.

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2015 Forester XT Premium
2020 VW Tiguan Allspace
teejay: If I wanted a comeback Id wank in front of a fan