Too much smoke and loss of power can be attributed to a clogged fuel or air filter (happened to me already). So better check the basics before taking the plunge.

May inline fuel strainer din ang 4d56. Sometimes it gets clogged. DIY lang linisin yun. Hindi ko lang mapaliwanag pero may thread about that dito dati (kaso baka page 20 na yun). It's basically a metal screen inside the fuel hose as it enters the injection pump.

Among the three I have no experiences yet. Pero ang Denso ang pinakamalapit sa lugar ko, eh.