I don't really know for sure, BUT, I suspect the trans solenoid are like the fuel injectors.
Some people buy bigger fuel injectors for their engine thinking it will give them more power and are disappointed when they find there is no power change at all. Well, first because just pumping more fuel into an engine with no other change just gets you less power, all your doing is richening the A/F ratio which doesn't make for more power. 2nd, becuase the electronic controls on the engine and trans are adaptive, meaning the sensors provide feedback on the how the engine/trans is operating and it adjusts the output to the things it controls to the engine/trans back to how they are intended to operate. So, bigger injectors just end up with the electronic controls shortening the injection pulse so that you get the same amount of fuel injected as you did with the previous smaller injectors.
Now, if you modified the motor with enough other mods that it was sucking in more air and needed more fuel, and was actually running short of fuel because you've hit the limit of what the original injectors can supply, then you would find a set of bigger injectors would actually make a difference and supply the fuel the electronic control is trying to inject but can't because the injectors are too small.
So, for solenoids in the trans, I don't know for sure, but they are still controlled by the electronics, so likely even if the solenoid operated differently than the OEM solenoid, the electronics would sense that and make adjustments to get the new solenoid to act and provide the same result which was the design, that is what the electronic management is there for.
SO, I would think changing the electronic management first would be the most fruitful mod to get a more desireable shifting trans. A new computer with different programming, or a hypertech that changes the programming in the existing computer. I also would make sure the Hypertech has the ability to mod the NAG1 trans beforing buying it, I don't know, but I think the Hypertech and other can't mod all engines and trans.
If I am right about the trans electronics being adaptive (and I can be wrong) the solenoids won't do anything. Its after you mod the trans enough that it would exceed the abilities of OEM solenoids, is where you would see the change if you went with them. For a trans, I imagine that would require at least new electronic programming and maybe even a modified valve body, then it may still be something like duty cycle and NOT speed of actuation or volume or things like that, i.e. you only need the high performance solenoids if you are racing and making the trans shift every two seconds for an extended period of time.
BUT, I could be wrong, maybe the blue top solenoids have different performance specs and the NAG1 electronic management does NOT vary how they trigger the solenoid based off feedback from the sensors, and changing the solenoid themselves do result in firmer/faster shifts.
I think the former scenario is far more likely, every electronic trans I have read about, modifies speeds and firmness of shifts based off feedback from sensors and the electronic management is looking to make the shift engage like it was programmed to do, i.e. how smooth or how firm. I would NOT spend all that money on the those blue top solenoids unless I had some very confident confirmation that the latter scenario was true.