I say the M2 handles the light loads fine, others may say different. I've used 2 3/4 dram 1 oz shot with no problems, however the minimum Benelli recommends (for all their Inertia Driven shotguns) is 3 dram, 1 1/8 oz.
The squishy parts on the stock uses material patented by Bayer AG Leverkusen. It's plasticizer-free, is used in the medical field, and according to the paperwork that comes with the gun, does not migrate, harden, or age. So far mine has held up great.
Carlson makes some good choke tubes. The ones you'll want for a CrioTech barrel are called CRIO PLUS.
The CrioChoke tubes are for the SBE II and M2. The Extended CrioTech tubes are for the Sport II and SuperSport models, and the regular Benelli choke tubes are for all others.