Performance mixed with fuel economy!?

That is very subjective. He actually wants to drive it, a lot. What is low performance about a 318 or 340? What is your criteria?

doesnt matter much what the criteria is, if he wants 300 or 500 hp
a 360 making a certain amount of hp will always be more streetable then a 318, or even a 340 making the same hp

especially since he has the 360 allready