I have a 1982 300d with an automatic transmission. The transmission went out so I am trying to find a manual transmission to swap into it. I have located a wrecked w115 with a manual transmission near me for cheap. I know there are some differences between the manual setup in the w115 and the w123. can the parts(petal assembly and the shifter assembly) be easily modified to work on the w123? I know I will have to make my own transmission mount, have the driveshaft shortened or lengthened, and have the flywheel balanced. Any insight is much appreciated.