This paper shows how subsidy design affects market outcomes in multi-product oligopolies when firms can adjust prices and product attributes. I show this in the setting of electric vehicles in Germany by estimating an equilibrium model of demand and supply of new cars. Consumers choose between cars with different engine types on the demand side and firms maximize profits by choosing the price and the driving range of electric cars on the supply side. I find that consumer surplus, diffusion, and CO2 emissions from new cars are optimized at different subsidy schemes. Inducing the sale of an additional electric car costs €0.76 in consumer surplus. I find that maximizing diffusion does not necessarily minimize CO2 emissions from new cars. This is because minimizing CO2 emissions requires substitution from relatively more polluting cars, rather than as much substitution as possible.