I dont think the virtual wall has been hit yet.
Again - it all comes down to one key item which Woody is chasing - ie: cooling. That maybe a tougher nut to crack than we think though.
Keep your AIT's down and your density will follow.
Again - dont want to sound like I'm preaching to the converted....but I've been thinking this since very early on in the piece, and the raw data is lending more and more weight to the story.

Unfortunately from what I've also picked up the stock Charge Air Cooler IC pump circuit is only good for 10-12kW (40,000BTU's) rejection.

The most representative rpm I could choose from the data for all 4 gear pulls is 4700rpm.
Plugging the AIT's and psi1/psi2 figures into my enigne calc/model yielded the following...

..Gear.......AIT..........SC discharge T*...Heat rejection from cooler...density kg/m3
1st gear....39C (101F)....97C (207F)......-21kW (71 kBTU/hr)...............2.55
2nd gear...44C (111F)....99C (211F)......-20kW (68 kBTU/hr)...............2.56
3rd gear...58C (136F)....101C (215F).....-15kW (52 kBTU/hr)...............2.50
4th gear...70C (158F)....103C (218F).....-11kW (39 kBTU/hr)...............2.45

*assumed 20C/68F intake temp.for every +5C = +7C to SC Discharge Temp (DCT).

Note - the max density achieved was at around 5400rpm was 2.7kg/m3
So you can see the density is dropping after peaking in the 2nd gear pull, also the rejection is dropping.

I guess without stating the bleeding obvious - keeping the AIT's down below 120F is key.....

Note - the high SC DCT's of 215 & 218F (based on 68F in) - I wouldnt be too alarmed by this....it aint boiling....
First, thats what's only entering the CAC gas side, that's gotta pass through the matrix of aluminium walls of the CAC where it will loose a few degF before it hits the water/coolant. Keeping your glycol up will also prevent boiling up well into the 110C/220F's, so no need to panic - unless you aren't running glycol....

The work by Woody is interesting on this part, but I dont have water temps - so can only guestimate here. The AIT's are measured as air passes out the last chamber of the CAC, which is seeing the incoming cooled water circuit. So I suspect the cooling circuit thermal inertia is already running up by the 3rd gear pull and AIT's are climbing.

For short runs - its possible that the thermal inertia of the large cooling tank setup (some have this) could be of great benfit here. I'm talking instead of the 2L/quart circuit you could run a 5-10L/quart circuit, thus delaying the onset of high AIT's until after your run and then it has the full half hour before the next one to cool down.

note - For those running OEM setups.....stock density is 2.07kg/m3 at 6,000rpm - so in this conversation we are talking here about 30% more density than stock - which effectively means 30% more power than stock - ie: these numbers are right out there.

Again - this isnt a tome in sucking eggs...just my thoughts and calcs.