ðə sˈuːbɚɹˌuː dɹˈaɪv tɹˈeɪn wʌz sᵻlˈɛktᵻd dˈuː tʊ ɪts flˈæt fˈoːɹ ˈɛndʒɪn dɪzˈaɪn bˌiːɪŋ ɐ sˈɪmɪlɚ sˈaɪz tə ðɪ ˈælfɚ ɹˈoʊmɪˌoʊ flˈæt fˈoːɹ bˈɑːksɚɹ ˈɛndʒɪn mˈiːnɪŋ ɪt wʊd fˈɪt ˌʌndɚ ðə bˈɑːnɪt wɪðˌaʊt ɐ lˈɑːɹdʒ bˈʌldʒ.
The Subaru drive train was selected due to its flat 4 engine design being a similar size to the Alfa Romeo flat 4 boxer engine meaning it would fit under the bonnet without a large bulge.