AEM CAI
Good: looks good, sounds good, can hear VTEC changeover even with SOHC motor
Bad: can't think of anything off the top of my head
Performance: it's probably about 3whp or something
Paid: $50 off a friend who totalled her civic and i reaped the benefits
Overall: what the hell - let's give it a 9

Cheapass Universal Muffler
Good: it was cheap
Bad: nothing- it actually sounds better than I expected
Performance: seat of the pants guesstimation - 5whp. no noticeable drop in low end, but much more responsive in higher rpms.
Paid: $75
Overall: not bad i guess. when i am not broke as fukk i will put a real exhaust on my car...

NON engine mods:

Denji Black Housing Projectors
Good: they look really nice (IMHO)
Bad: light output less than stock
Performance: see "bad" above
Paid: $199 about a year ago
Overall: they're coming off my car.

shameless advertisement: i'm selling the projector lights for $100.

yes, that's all my mods. i'm broke. bite me.