I think Mike's experience is interesting. I've got a M1000 and M6r and on some patches they sound similar and on others the differences are very audible - so it might be that on some of the patches in Mike's m6r no difference can be heard, but on others....

The info on the different filter design of the narrow and wide packages came to me from the head honcho at Wine Country and as I can hear a difference between the M1k and m6r it makes sense to me.