correct me if i'm wrong, but...
 

i have a '91 civic hatchback, and i'm pretty sure it has one of the d-series engines in it. i'm tryin' to crank some more horses out of it, but i'm not sure if it's worth puttin' money into. it has about 113,000 miles on it. i also want to stand a chance against the rsx, civic si's, and integras. check out my sig for the mods. would it be worth it to do a swap? i want to take the cheapest route, but get somethin' that's potent enough to stand a chance, and highly upgradeable in the long run. what do you guys think. b-series? if so, which one? or should i stick with my D?

ditch those 3.5" drop springs, they are only hurting your performance. id ditch a lot of things you have but thats just me, you probably like your car and thats cool.

anyway, you can swap in a B16A and get right about where you want to be.

Ditto

your best bet is the b16. its the easiest, cheapest, and most availibility for parts. and you can make a ton of power

definitely go with b16a. especially seeing as how you have over 100,000 miles. there pretty darn cheap too.