Sure, but the problems with the old suspension need to be kept in mind for this conversation. Our front was sitting on the bumps on every turn. Our rear was probably bound up pretty often.
Lets say that with the old springs our car should have rolled 5deg at turn X. But instead it rolled only 4deg because of the bump stops. So now we put on significantly stiffer front springs, and somewhat stiffer rear springs and turn X makes our car roll 4deg now. Add to that, the driver plays with his front ride height a bit and now the car can only roll 3.5deg before the outside front corner pins itself on the bumpstop.
In the absence of bumpstops, sure the car would ride flatter with the newer springs. But we can’t say for sure it’s flatter now just because we can now get off the front bumpstops. What we can say it that the spring curve is more flat. So it certainly takes more g’s to get the car to roll. If one raises the front up enough, at some point the stouter front springs will keep the car off of the bumpstops well before that would have happened with the old wimpy springs, given the same lateral g’s. But we don’t yet know the interplay of all that yet.
Sure, if your front is the same height as before, you’ve got 2mm more bump travel then you used to. The thickness of the old spring hats is the difference and they are ~2.4mm thick. I measured the heck out of all of this. So it would take 40-47% more lat g’s to get you to roll on to your bumpstops. Actually a hair more because of the 2.4mm. Therefore the car will feel much stiffer in roll and you’ll smile all the way thru the fast sweeper. Ride height being equal, you’ll spend much less time on your bumpstops. But you may still end up on them, and therefore the actual amount of roll of the car may be the same before and after the change of springs. We just don’t know.