[Vekke]

What comes to intercooler off, temps on my Lupo 3L are now with steady throttle and no grill block at the moment:
80 kmh = 40 celsius
100kmh = 48 celsius
120kmh = 70 celsius
Outside temperature 13 celsius and wet.
On winter if you have a intercooler those intake temperatures will be on minus for the first 10 kilometers and your engine will warm up slower. There is no power gains to be made if you feed minus celsius air to your engine at least with my current knowledge. You should try to get the engine warm up not froze it.

They have propably reached those power figured with bigger intercooler for sure, but if you are hypermiling your acceleration times will be so short that intake temps wont have time to raise so high that you would need it. The intercooler propably also flows better but if you take it all out its har to beat that in flow efficiency. Every bend in your pressure pipes makes little drag and depending on how many bends you have the turbo has to work harder to be able to produce the same boost level. Usually the pressure drop is about 0.1 to 0.15 bar.

On summer in a big truck you propably still need it but that can be tested with fuel consumtion meters like ultragauge etc where you can see the intake temps.

Oh and in Finland and Sweden the winter temperatures can be as low as -35 degrees celsius or -31 degrees fahrenheit. So the biggest problems are to first get the engine running and after that make it warm so that you dont need freeze inside the car.