It was built for those events so it has a sump-guard mounted on 'welded-on' brackets, it has an additional fuse-board for tripmeter (diff-sensor), map lights, relayed headlights, 2nd fuel pump. Master 'cut-off' switch, navigators footrest, harnesses and decent seats, safety devices roll-hoop. The engine (2.8) is built for mid-range torque and economy. Ok other cars have this but it has a Quaiffe LSD.
Hugh's rally car will be more 'hard-core' and so I couldn't imagine it being comfortable for say a 3 day event. It will be louder and like your car it will be revving it's nuts off.