A standard Cavaliabra has a transverse engine with a transfer box at the front diff, like a Golf Syncro or similar FWD to AWD conversions. I think that the centre diff is in fact at the back, ahead of the rear differential; that's the common arrangement with these systems.
This is a RWD conversion putting the platform and running gear of the Lotus Omega into a Calibra bodyshell, performed by a German tuner famous for producing nuts cars, like (IIRC) the Porsche 911 engined Mk 1 Golf GTI that could lift the rear of the body to show off the engine to cars it passed.
Richard