you need to think about how much heat energy you need to get rid of first, and this will tell you how big your peltier device would need to be and how much power you would need to drive it

and don't get confused thinking that because you are cooling something that is 'quite hot' you are doing a lot of cooling work. there's more to it than that

for the charge air;

cooling power = mass flow x change in temperature

i think that the mass flow rate of air is pretty high for a turbo engine at full chat, so your cooling power requirement will be quite large