Adrian, You have focused on body mass and proportion issues but one can influence the perception by changing the wheel and tire proportions. Yeah, there is the outrageous diameter thing but I have sought subtle influences with two projects. I have restyled an old Brooks Stevens Series I Excalibur Phaeton into a 1929 Mercedes SSK Roadster. The E-cal had 15 inch wheel/tire at 27 inch OD. That results in 3.2 diameters between tires. With my 18 inch wheels and 30 inch tires, the spread is 2.6 diameters. The Merc SSK wass 2.4 diameters between. In comparison the Excalibur looks wrong. I also have a replica of a Ferrari Dino.The Dino originally had 14 inch wheels and 24.9 inch diameter tires; 2.7 diameters between. My replica has exaggerated fender proportions and 17/18 inch diameter wheels.with 23/24 tire diameters. That results in 3.0 diameters between and a more contemporary aggressive look. The replica tires are quite wide, and they need it.