So basically you're telling us that by lowering the noise floor, your tone is not going to change ONE BIT??? I disagree. When you LOWER the noise floor, you are 'removing' noise from the equation. When that happens, there is sure to be more clarity than there was before, correct? Add a TINY bit of noise (distortion) to your amp and tell me it does not sonically change the tone of the signal. Better yet, put an O-Scope to the output of a II and an XL...I guarantee things are going to look different.
Also, because of the fact that there is lower noise, and MOST PROBABLY (I may be wrong here), the same threshold level is still in the XL as the II, it is going to be LOUDER...like I said before, not much, but it will be.
Now, take into consideration different hardware...The XL apparently has different hardware, so why should it NOT be faster than the II? Everyone is going off of preconceived notions that they know everything about these devices... Call your bullshit, I'll use my 20+ years of real world experience to stay informed...