agreed. one of the huge factors is letting the engine warm up before taking off and wait 10mins for the engine to full warm up before laying into it. i did this with my 04 k24a2 with blower ran amsoil the whole time. after 42,000 miles i didn't really lose much power on the same dyno i tuned on, about the same time of year on the tune and and retuneThe engine will make 400 with a supercharger in stock form. But your components you have already purchased will work just fine for SC application (assuming the CR isn’t super low ). If you build the engine with what you have it should last forever at 400whp , definitely longer than the gearbox will.