The North American P-51K Mustang makes an interesting choice. The original was differentiated from the famed 'D' mainly by the propeller, which was made by Aeroproducts, instead of Hamilton Standard. Some canopies also differed slightly, though this was more likely due to production variations, rather than a planned redesign.
Two Airfix rally cars are now presented together, and very good they look too. State of the art racing machines feature in the form of a Ford Fiesta WRC and a Mini Countryman WRC. The single-car kits are very good indeed (and are especially well presented) so the Twin-Pack makes a good way to buy the two at once. Paints, brushes and cement are included.
This is a big Airfix growth area, and I've nicknamed these kits 'the droolmakers' as they are so desirable.
Here's another background group, in the form of a World War II Bomber Resupply Set. A range of hardware is included in this interesting offering, including a wheeled high-level work gantry, wheel chocks, folding ladder, even an RAF-issue bicycle.
More information from Airfix.