FLM threatened legal action. Conversions could be carried out at any time in the car's life. Most conversions appear to have been carried out when the cars were 12 months old or older because if a car was converted when new, the conversion would be liable for Purchase Tax like the car itself. Due to the cost of the conversion (about GB£800) it would appear that most were carried out on the 3500 rather than on the 2000, with even fewer 2200s made. In comparison with the Triumph 2000 estate, the Rover Estoura was of limited practicality. The quality of the conversion also left a great deal to be desired, with the estate conversion being pop-riveted on to the back end of the modified vehicle, with little rust-proofing or paint applied. As a result, the back end of the vehicles often rusted out, and several estate "pods" were subsequently transferred from one car to another. NADA models Rover made an attempt to break into the North American market with the P6, beginning with the Rover 2000 TC. One version of the P6 that was exported was the NADA (North American Dollar Area) model, equipped to a higher standard than UK cars. These are also often referred to today as being "Federal Specification". Notable differences on the outside of the 3500S NADA were wraparound bumpers, three air scoops on the top of the bonnet, front and rear wing reflectors and the "Icelert" on the front grill. The "Icelert" was a sensor which warned the driver of falling outside temperatures and the possibility of ice forming on the road. Inside, depending on the location, the US 3500S was also equipped with electric windows, power steering and air conditioning, all of which are extremely unusual in UK market P6 cars. The earlier 2000 and 2000 TC NADA featured the Icelert system and the side reflectors only. The NADA P6 introduced features which would later appear on the UK Mark II car, including a new instrument cluster and seat piping. Despite being badged as "3500S" cars, the export models were all fitted with the Borg Warner 35 automatic transmission. The cars were not popular with American buyers, but were sold in Europe instead as they were already converted to left-hand drive. In true British Leyland fashion, several UK cars also ended up with single scoops on their bonnets in an attempt to use up