+15whp +19wtq mid range without tuning. Even more power with tuning! Comes with new bolts.This manifold riser extends the length of the intake manifold runners which allows airflow more time to reach optimal velocity in the mid-rpm range which in turn increases mid-range torque output which the 3.8 really needs! Additionally, it extends the torque curve to continue producing torque further up the RPM range. With a custom tune, the peak power is shifted higher in the RPM range. All of this means greatly improved performance from your V6!This raises up your manifold by 1″, your intake may need adjusting, you will not be able to use your engine cover anymore and you will need to either do a coolant bypass on the throttlebody, or extend the coolant hoses.Using a phenolic spacer is NOT recommended as it may cause clearance issues with the stock hood.Note: If you’re canned tune, you will need a custom tune. If you’re custom tuned, you will need a retune!