In early 2008, Australian engineering staff tested the IS 250C for dust intrusion, air-conditioning, roof and driving performance in the Northern Territory.
Roads between Alice Springs and Darwin were used to test overall durability of the vehicle, with emphasis on dust sealing and roof integrity.
In the heat and humidity of Darwin, engineers tested limits of climate control performance.
Climate control testing involved a process called heat soaking, where a black vehicle was left closed and unprotected in the broad daylight, allowing internal temperatures to reach in excess of 100 degrees Celsius.
After four hours in the sun the vehicles were then started and climate control units evaluated for performance and cooling times.
Engineers also carried out real world testing on aerodynamic performance to ensure that, with roof up or down, IS 250C occupants were not buffeted by wind.
The results of the Australian testing were fed back to Lexus engineers resulting in revisions to climate control systems and dust sealing.
Engineers also tested the strength of roof locking mechanisms on corrugated roads.
Testing confirmed that scuttle shake, when a closed roof rubs against the windscreen surround, was minimal on even the harshest roads.
Lexus Australia, Chief Executive John Roca said that the testing cements Australia's importance for the global brand.
"Australia has played host to the testing of numerous Lexus models including the first ever Lexus, LS 400, and the LX 570 luxury SUV," said Mr Roca.
"IS 250C is truly a convertible for Australian conditions - it has been designed to offer occupants a comfortable and enjoyable ride no matter what the road or climate.
"Australian engineers were extremely impressed with IS 250C's performance, noting that dust sealing and scuttle shake were the best they'd seen in a convertible.
"The new IS 250C also extends Lexus' IS Line and will join its sedan counterparts on Australian roads in the third quarter of this year," said Mr Roca.