SPOON N1 EXHAUST BACK BOX SILENCER HONDA CIVIC TYPE R EP3SPOON SPORTS N1 Back Box. The Spoon N1 exhaust silencer was developed and used on Spoon's race vehicles and is the ideal back box for the street and circuit enthusiast. The N1 back box provides significantly improved exhaust flow and can be used with the stock b pipe as it uses stock style flanges. In addition, the N1 back box is one of the lightest available, weighing only 7. 9lbs (3. 5kg). The tip is 65mm, same size as stock, providing a subtle