?I have the b16a1 in my 91 crx and purchased a 4-2-1 dc header. the one o2 sensor bung for the header was by the cat like its supposed to be for usdm. however, i saw the 2 o2 sensors for the b16 go up towards the top when i received the engine and original headers. so i basically eyed up where the holes were and marked them on the dc 4-2-1 and got bungs welded into it and put the o2 sensors there. was this a big mistake? i have an a/f gauge too but i'm thinking it might not be accurate and tricking the computer b/c of what i did to the header and o2 sensor placement. what do you think? ?