DaveW will be along to provide the definitive answer, but as far as I'm aware, all current trads are based on the same chassis, so body tub width/length is the same.
Overall width varies according to the wheel widths used, as the wings are cut to suit. Most 4/4s have 5" rims with 165 section tyres, most +4s have 5.5" section wheels with 185 or 195 section tyres.
Most 4/4s have 1600cc or 1800cc engines, all +4s have 2000cc engines.
