I know you are being facetious but XT and regular MultEQ have very high resolution subwoofer filters. Only 4x less than XT32. It's the bass in the satellite channels where the most drastic difference lies.
In the midst of this lets not forget that you can still have a wonderful sounding system with lesser versions of MultEQ. Obviously if you are buying new the only reason not to get XT32 would be budgetary as Chris K notes.
Concerning the resolution. XT does ~11ms of correction with a FIR filter. This translates to ~91 Hz of the frequency response resolution (this could be "simplified" for understanding as a minimal distance between two peaks or two dips on the pre-out graph). So, if we are looking at it in the logarithmic scale there are much more resolution per octave for high frequencies than for low frequencies. This is the nature of FIR filter.
Then when we go to XT32 resolution is 32 times higher, so it is less than 3 Hz. For all channels. And the subwoofer channel of XT has 4 times less or ~11 Hz resolution.
Look at the graphs posted earlier and you will see pretty much that!