So, it's pretty simple to see that the VX totally wanks on the CX, and that the CX totally wants on my DX, so I know the CX I have will be an upgrade, and the VX I want will be from there, also.
However, you can't do a cylinder head swap on the DX with a VX head without a very high compression motor (very small combustion chamber mated to dished pistons in the VX block) so I've been thinking about an HX head.
The HX makes 23 more HP than the VX, but I figure that's mostly in VTEC, and it also has a 1.6 and not a 1.5 like the VX. But anyway, the HX doesn't have super small parts like the VX, but it has VTEC-E, and I know it's a step up from the DX, but will it be a step up from the CX if I choose to buy one? Iono, and I certainly don't want to do A-B-A with head swaps, not that it's even possible, but yeah...
I think you are too optimistic on the VX, at least in my case. Remember, my engine is either under load, climbing a hill, or it is off. I doubt that I could climb a hill in lean burn mode so lean burn is not feasible during my commute. There may be some small gains due to reduced internal friction, 200 lbs less weight, better aero drag and a taller tranny. I'm hoping for 5-10%.
Now for highway cruising, that is a different story. Lean burn would work great for that. I just need to find the highest speed that will allow for sustained lean burn and hold it just below that speed. Hopefully 50mph or above.