I wouldn't try the recirculation of boiling wort with our cheap pumps. I fear that prolonged exposure to such high temperatures will certainly shorten their life expectancy.
The thing of boiling half the time with the lid on makes absolutely no sense. With the lid on you're reducing the radiative losses from the surface, with the lid literally acting as a mirror and reflecting the radiative heat back into the wort. This makes the wort boil more vigorously because there is more energy available for the vaporizatin of water, so basically you are boiling with higher available power just like you would do with a higher power setting.