If you've got $5,000 for performance, then I'd say either get a GS-R motor with only a coupe bolt-ons (what you can afford) or a B16a with intake, header, exhaust and possibly some cams and an Apexi VAFC. The GSR will be more expensive than the b16a but basically has more hp. The reason I say basically is because the US version has 170hp, the same as the JDM b16a; but it has more torque. Also you may want to consider an LS motor. Even though it has less hp (142hp) it has a little more torque than even the GS-R motor does. So here are our choices...
B18c(1) [GS-R]: 180hp JDM, 170hp US
B16a(3): 160hp US [b16a3 Del Sol], 170hp JDM
b18a/b [LS]: 142hp US, 145hp JDM
Or if you're feeling frisky, get an Si/EX motor (d16z6) and do a homemade turbo kit on it. For around $1,500-2,000 you could have a decent turbo kit and make anywhere from 170hp+.
For intakes, a lot of people get the AEM Cold Air Intake, it's one of the best CAI's out there. For a header, a lot of people go with the DC Sports. As for exhaust, there are tons of companies that make cat-backs; it really depends on how much you're willing to spend and how loud you want it.
Don't let some of the people on here bother you. Most people have been here a long time and just hear the same things over and over again, and come to their own conclusions on what they think is good for a car and what is not. I personally am one of them. Though I've begun reforming my ways, and realizing that it's more constructive to help people out than just make fun of them for something that's none of my business. Just have fun with your car, research it and do what you decide is best.