The same taxi and driver that takes Frankie from the airport to meet Charlie is the one that drives him back to the airport, many days later.
Towards the end of the film, Ronni is seen to be wearing a camouflage shirt. This shirt was part of a uniform issued in the British Army known as Soldier 95. As the name suggests this uniform was issued in the mid 1990s and so would not have been available in the early 80s.
The scene repeated twice, when Frankie and Charlie are on the run right before attacking the guys doing drugs, both pass in front of two girls, one is wearing the "Frankie says Relax" t-shirt but, on first the take, Charlie looks at her and says: "fuck off". It must be a warning of things to come.
The film is set in the early 1980s however the alloy wheels fitted to the Porsche 928 featured in the film are from a much later model and weren't available until 1994.
In scenes set in Spain, a red-tailed hawk and a cactus wren are heard in the background. Both these bird species are found only in the Americas.
(at around 21 mins) Frankie throws his cigarette to the floor and treads on it. Only his toes miss and kicks the still-lighted cigarette under the right foot of the other character.