Hey Jimmy,
I'm a new Civic owner too, Cept I got a HX Coupe. Basicly with small displacement engines every little bit counts, building up HP is not as easy with a V8. A nice set of Headers will replace your stock Manifold, but You'll still need a cold air intake, to replace your stock air intake. AEM is pretty agreed apon to be the best. I'm not too intirely sure what is out for your car as of yet though.. I mean the SI's are brand spankin new, and it's an entirely different engine than the EX/HX or LX/DX . So you'll have to check around. .. Check out
www.2k1civic.com I hate to spam other sites here on Honda style .. but it's a nice site for our cars, but the forums thier kinda suck !
Best of luck, and nice choice on the Ride.