The spacer lifts the plenum (increasing runner length) and offers loads of advantages such as:
1. The upper plenum sitting taller allows for the fitment of aftermarket fuel rails/injectors with the stock styled plenum tops.
2. With an added 16mm of intake runner length, the engine will gain a small, but noticeable, boost in torque across the lower section of the rev-range.
3. The added torque is known to reduce turbo lag, bringing boost on 100-300rpm earlier.
4. Off-boost performance is also improved, which usually nets a small gain in fuel economy.
All these benefits increase driving pleasure.