The gag is very funny, and on top of that also has wholesome moments too like with his friend (and former enemy) Godai.
Also I can't help but think the style is somehow similar to Harold Sakuishi, maybe the mangaka (Ozawa Toshio) was his former assistant?
Nanba MG5 is hella funny! The story is about a Nanba Tsuyoshi who lived a double life as the youngest son of the strongest yankee family in Japan, and a normal student who just wants to live a normal life. The manga is a real gem.