2 stage or modulating furnace with variable speed HP?

I am getting ready to update my hvac system and have pretty much decided on a Lennox XP25 (3ton) variable compressor heat pump. My problem is which matching furnace would be appropriate with this unit. The SLP98 modulating furnace, or the EL296 2 stage? The installer convinced me of the duel fuel concept, and initially recommended the SLP98 to compliment the XP25. After I asked him about the 2 stage EL296, he said that unit would perform well too, and that while he recommends the SLP98, the EL296 is still a good choice, and ultimately it's my call.

Since I will be using a duel fuel setup with the icomfort s30 stat, wont much of the modulating ability of the SLP98 be unused? Since the theory is that the heat pump would be my heat source until the outside temp gets to around 25-30 deg F? At that point the call for gas should be enough that the 2 stage can run a long time on low, and then switch to high on really cold days? If it were only a few dollars difference I wouldn't even ask, but the quoted price difference is around 20% between the two furnaces.

I live in central Illinois, so winters can be severe at times, and I value comfort much more than effeciancy. The installer is also putting in an Aprilaire 600 humidifier, running on hot water.


Thanks in advance