How do I know it can be done? I just converted a five speed '88 260e to A/T using the transmission and all related components from an '88 300e. Extremely straightforward conversion with a little guidance from SteveBFL. Included is the 5speed gearbox with linkage rods, crossmember and mount, driveshaft, flywheel, and clutch, shifter assembly, pedal console with clutch master cylinder, clutch slave cylinder, and master cylinder fluid reservoir. The front driveshaft flex coupler needs to be replaced and it might be a good idea to install a new clutch if the car is going to be driven aggressively. Asking $1000 obo for all components, you pay shipping.