Discussion and technical advice the SW20 MR2. 3S-GTE, 3S-GE, 3S-FE etc
Anything and everything to do with maintenance, modifications and electrical is in here for the Mk2.
DIN is the standard size for car audio receivers/modules and ISO 7736 defines a standard size for car audio head units.
The standard was originally established by the German standards body Deutsches Institut für Normung as DIN 75490, and is therefore commonly referred to as the "DIN car radio size". It was adopted as an international standard in 1984.
Head units generally come in either single DIN (180 x 50 mm panel) or double DIN (180 x 100 mm panel) size. The depth is not standardised but DIN is a standard measurement so it should fit.
I hope that helps