I’d have to look more closely at the measurements (I only have a very early MOD) but I think it must be better than 40dB S/N. If there is a DC offset, that’s a different matter - in and of itself that could mainly affect dynamic range etc instead - but without knowing the cause this is only speculation and I guess not very helpful. This whole discussion about gain levels seems very messy - having gain trims and twiddles everywhere is an engineers solution (and not a very good one) - its not a musicians solution (speaking as a musician rather than a developer this time - I just want to play - and it would be nice to leave some CPU for other effects too… 
). I don’t know what the right answer is for everyone (or even if there is one) - the MOD is trying to be extremely flexible - and there are those who would want to use it in between guitar and amp - just like regular stomp boxes, or those who use it in an effects loop etc. The best solution (or least worst) is to design effects intelligently, with the idea that they have to accommodate a wide range of levels, and not get too hung up about it - (guitar players especially) have been abusing gain structure incompatibilities to great effect forever. For example, with the DT-1 distortion, I designed it primarily to work with ‘guitar’ levels, but, the gain goes from 0dB to 40dB and the output level can be set anywhere from -Inf to 0dB so it should be possible to find a setting that works (others may disagree - I won’t be changing it)
We talk about a difference of 25dB, which is a huge diff, especial for a distortion algorithm.
I’ve developed a new distortion plug (coming soon) which comes with a selector for the input level. It covers the settings for the input stage low | mid | high. The selector is only available in the settings frame, not on the UI. It allow to archive the exact same behaviour of the plug across any chosen input stage level, when the setting in the plug match the setting on the MOD.
When the MOD host would provide the input stage gain setting as a feature to the plug, it could be automated so that users ain’t need to care about.
With the DT-1 distortion, its designed to work down at “guitar” levels, so if you want to hit it with something e.g. 20 - 25dB hotter, that’s fine, just turn the gain / drive down (about half way). There are different solutions to this issue, which work best depending on the plug-in and / or the distortion algorithm. In my case I set out to model an analogue distortion box that you might (normally) put in the guitar signal path - I found something that works for me. I hope it works for other people, but I don’t know if anyone else has even tried it.