yeah. way more air flowing through a 5.0 box. If you put them side by side you will see a big difference. Problem is, the 2.3 doesn't flow enough air to justify swapping to a 5.0 box. It is a waste of time. So is a cold air intake on a 2.3. It just doesn't flow much air and the stock airbox if functioning properly does not choke it. The 2.3 box also has a heat riser valve built into the box which is open on the highway, closed when there is no vacuum (full throttle)--and disabling that reduces MPG, quite a bit actually. Mine was seeing constang 27mpg and then I found out that someone had disabled the valve in the box, so I pulled the plug out of the vacuum hose, put it on the valve like it's supposed to be and it was seeing 35-36 mpg on the highway. 93 hatchback 5 speed.