From "Ferrari" by Hans Tanner & Doug Nye:

At this time the Scuderia Ferrari owned eleven Alfa Romeo 8Cs - six of them Monzas and five the Mille Miglia sports models, plus two old 1750s, the so-called Duesenberg and a fleet of Rudge racing motor-cycles which they campaigned in the manner described in the Appendices.

...

It was this race [1933 Italian Grand Prix] that the Scuderia Ferrari entered Trossi with the 4.4-litre Duesenberg, but this news could not attract the public's attention away from the expected duel between Campari with the Ferrari Alfa and Borzacchini with a Maserati, the latter out to show up his former team. The first heat was interesting enough, Trossi lead the race until it broke allegedly dropping oil on the track.

Unfortunately the race is not universally remembered of this truly oddball entry, but rather a series of fatal accidents:

Campari had overtaken Borzacchini on the banking and being at the absolute limit, had been unable to hold on and gone over the rim of the banking. The unfortunate Borzacchini, in an attempt to avoid Campari also went over the top of the banking. Campari was killed outright and Borzacchini died twenty minutes after having been taken to hospital. The day was further marred when in the final, Czaykowski crashed to his death with his Bugatti.

On what unlikely 'luxury car' would you put the prancing horse?