theyre easy to put on my engine because i had some ram tubes spun up which fit onto the ends of the quad-throttle manifold. youll probably like to look into these before you try & cable tie some filter socks directly to the ends of your throttles like ive seen some people do...
the oxygen sensor is where it's supposed to be... in the exhaust, just before the catalytic convertor. (ive got 4-2-1 extractors, so thats the closest i could get to the engine itself)
why do you wanna know about the oxygen sensor? are you talking about the air flow meter???