[oil pan 4]

Its all about being able to hit a target temperature and pressure.
In a spark ignition engine you want to get your air fuel mixture as hot and under as much pressure as possible before lighting it with the spark plug.
If you get the air too hot the air fuel mixture could preignite and that would hurt fuel fuel economy and power.
Most vehicles in factory form stay well below that temperature and pressure preignition threshold.
This is one of those mods you really want to A-B-A test to make sure you dont hurt fuel economy.

The next gasoline engine I build I will get the temperature and compression into that ideal range by raising the compression ratio up to about 12:1, using a cold air intake.

A diesel engine is a little different. You always want a cold air intake, the diesels seem to respond best to cramming as much gaseous mass into the cylinder as possible. That is why deleting the EGR and running water mist injection works so well.