i found something out about this today, the gsr O-rings consist of two parts: 1 rubber ring (2mm)and 1 plastic ring (2mm)but as the gsr never came out over here i had to buy type R ones which was a bit of luck because the type R ones are a one peice rubber ring (4mm)which completely replaces the two rings on the gsr.
and wow what a difference with the hood closed i can't here the engine running