Carmaker Audi is instituting a material shift, and metal castings will be a clutch part of the conversion.

According to a recent article from U.K. media outlet Autocar, Audi is doing away with the steel monocoque chassis traditionally used on its cars and moving to aluminum construction for all models except its A3 and A1 lines.

Check out the article in Autocar here, or if you don’t have time to pore through it, here are the metal casting highlights:

“The essence of the structure is large aluminium castings for key areas including the front and rear chassis legs, the front suspension mounts, the base of the A-pillar and the front section of the transmission tunnel…At 1.4m long, the new A8’s rear chassis leg is said to be the largest diecasting in the world. The A8’s door structures are now also cast in one piece…These castings (which are also a crucial element of the safety structure) can apparently be used to underpin all Audi models based around longitudinal engines…The rest of Audi’s new body structure (including the sills, roof structure and floor sections) is made of inexpensive aluminium extrusions that can be easily cut and bent to size.”