The SP2S Dominator 3 (D3) exhaust adds about 2 hours more labor time to complete the manifold and an extra 2 hours of labor in the stinger section of the pipe. It also adds dual point, dual stage water injection to the stinger section which is far superior than a single point, single stage water injection delivery system. The D3 also adds a secondary cooling line which adds 100% more cooling water. The original D2 and your "stinger" set-up robs 35-40% of the engines water supply needed for cooling. The latest D2 config uses the same dual inlet waterlog of the D3. The D3 is also alot more sophisticated as far as installation and takes a couple of hours of tuning on the water to get the most out of it. The result is a 20-22hp gain, phenominal bottom end (hair trigger throttle response) and better pull through the mid range with up to 2 to 3 mph gain depending on other mods you've used to complement the system.