The way I remember it was that the estate version produced less lift at the rear, but as you said primarily marketing. The following year all the cars sprouted large wings (thanks to Alfa :roll: ) and so TWR went to a saloon shell.
I found this nice little photo from Le Mans in 1987. Tom himself sprayed this graffitti after getting a drubbing at the hands of the factory Porsches. Ever true to his words they returned victorious the year after.
Cheers Tom and thanks for the memories.