jdmb18clsd

ok so i have a 94 ex coupe it has no exhaust and i have a motor from my old car id like to put in its a b18 with jg 4-2-1 header. on my old car i had basically some steel braded flexpipe after the header and pipes bent straight back to a fart can from a buddy that worked at a exhaust shop. ive been looking at all the exhausts (catbacks) for civics my problem is that i dont want to run a cat so i will obviously have a gap between the header and the "catback exhaust" i would buy. does anyone know 1) how big this gap will be if i get a catback. 2) what i would put between the header and catback.
3) i would also like to run o2 sensors on this car if necessary however the header bung for the o2 is placed in a spot where the o2 would hit the oil pan. anyone know what to do i kinda wanna keep this on the cheap but the more i look the more i want to buy a really nice apexi exaust for it but im worried about the mods id have to make between the catback and header.
id rather go straight pipe but i have no one to bend it. and if i go catback should i get a hi-flo cat, add restriction to my exaust and run o2 sensors also did the 94tegs have 2 sensors or only 1 bieng its obd1 i am not totally sure. any helpfull feedback would be greatly appreciated.