Ok, in that case you can use either a P28 if you don't care about a knock sensor, or a P30 if you do. They're actually the same base hardware but the P28 is missing the extra circuit board inside with the knock sensor stuff on it. Anyway, you could also use a P72 and run P28/P30 code on it, but P72s aren't as easy to come by as P28s.
I'd say go with a P28 and don't worry about the knock sensor. If you have a good tune it won't matter anyway, and every 92-95 Civic EX came with a P28 in it so there are plenty of them out there. You should be able to find one for around $75, chipping will cost around $50 and can be done at the same time as Hondata installation. If you can find an auto tranny P28 (which is usually cheaper; I've paid $35-$50 for them) it can be converted to manual tranny useage for really cheap during the chipping process.