Toyota and Subaru are joining forces to develop a sensational new sports coupé together, shown above in an Autocar image.An inside source revealed top-secret sketches, showing that the car’s brief is to be compact, lightweight, rear drive and fast. Although the Subaru and Toyota versions of this coupé will look different from one another around the front and rear, both will be powered by Subaru’s 2.0-litre flat four engine, making this the first time that a Subaru boxer engine has powered a Toyota.A naturally aspirated version of the petrol boxer engine with 175bhp is being considered for the base model, and there is potential for a hot 2.5-litre turbocharged model later. This will be a car inspired by the classic rear-drive AE86 Toyota Corolla GT coupé from the 1980s, a car known for tail-happy handling. Yet beneath the skin we can expect a reworked Impreza, shortened, lightened and with a bespoke coupé body.Subaru’s trademark four-wheel drive system will be ditched to save weight, complexity and cost. However, if the standard model is a success then later plans could include a spiritual successor to the Toyota Celica GT4, featuring the 2.5-litre turbo boxer engine and four-wheel drive.Affordability is the priority for this so-called ‘Toyobaru’. Costs will be driven down thanks to technology sharing between the two car makers. Sources suggest that the coupé could cost as little as £10,000 in Japan, but it’s likely to be closer to £20k in the UK, rising to £25k for the turbo model. Subaru will build the car at its Gunma plant in Japan, while Toyota is in charge of development. The final design of the coupé is due to be signed off in July, with production set for 2010. Toyota, which holds an eight per cent stake in Subaru, is said to be keen to attract Japan’s disaffected youth with a Mazda MX-5 rival. In fact, an open-top derivative of this coupé could be another longer-term option.After a launch in Japan, it’s believed the new coupé’s main market will be North America, but it should also make it to the UK. There’s a big market here for sports coupés and Toyota could benefit from an enthusiast’s car that revives the lustre of the Celica.