Looks good, just make it weight 1400kg and put 3-3.5L inline six engine with magnesium-aluminium block and engine weigth only 160-170kg maybe less. Power 300-350bhp 7000-7500rpm. Porsche 991 is NA, why Bmw can´t make that?
Before somebody says FI is better engine, yes some car. NA engine don´t need turbos, intecoolers etc. N55-engine weigth 190kg whit magnesium-aluminium block, M52 with aluminium block only 160kg. M3 F80 need turbos to get over 400bhp, but M2 don´t if they make it weigth allmost same than e30 M3.