I haven't found any topics or discussions on this so I thought I would bring it up here. I know the 4 hole injector upgrade is the accepted standard but, I'm looking to see if the 12 hole fuel injectors would offer better performance and fuel economy. I'm looking to upgrade my intake manifold to the newer style ones in the near future, so I figured it would be wise to upgrade the fuel injectors to accompany the install.

The more holes the better?

There's a point of diminishing returns with most everything in life probably including 4.0 fuel injector upgrades.

I did notice a little better low end torque and no more bogging off the line when i went from stock 1 holers to 4 holers.
Far as better gas mileage? Same 'ol same 'ol gas hog.

Flow rate also needs to be correct.

i saw 0 improvement of anything when i swapped injectors.

I got smoother idle and snappier throttle response.

What's your fuel setup if you don't me asking?

I just got smoother idle, no change in throttle response or gas mileage.

Still worth it though, better atomization of the fuel is always a good thing but I do agree with the diminishing returns notion.