I know the proton is disco as is the mr42 at this point I have three of each, there is already a problem getting parts for the proton ie the replacement purge buttons, how long should I be able to get parts for the mr42? the poppet is the item I see being an issue. hopefully Zak has some insight he can share... I have a pair of carbon mr42's for doubles, great regs but really only 5 years old and I would really like to get at least another 5 years out of them.