I see tons of M1's for sale and a new M2 with no extras is running anywhere from $895-1000. The M1's new are high $6's-800. I know the M2 has new reciever dimensions and you can buy a new comforttech stock for it but other than that what's changed??

Other than what you described there is not much .

The M2 has over the M1 other than the fact that the M2 recoil is reduced compaired to the M1. The trigger guard has changed and the new Benelli M2s use Beretta's Optima bore and cryogenically treated barrel.

To me the Benelli M1 is a great design, and people say the M2 is an imporvement over the M1. But I still prefer the M1 and the fact you can use tube extensions.

Chris