How come in 4-cyl performance cars, they usually for 2.0L of displacement instead of going up to 2.4/2.5...

How is the 2.5L QR that Nisssan made? They put that in the Spec-V Sentras.

2.0l ecoboost has a balance shaft

Was ok but had issues early on. Precats were too close to engine and if the material broke apart it could be sucked back into engine leading to oil burning. Theres turbo and supercharger kits for it as well.
I remember it as torquey more than rev happy but i had stock altima with autotragic. The 5/6 speed are way better

It's for MPGs because they are all just econoboxes