You can find some good Invidia N1 deals, check the member's section people on here are always selling them.
http://www.ft86club.com/forums/showthread.php?t=95668 - 500
http://www.ft86club.com/forums/showthread.php?t=97870 - 460 Shipped
If you wanna spend a little more go with the Tomei Type 80, great catback especially if youre gonna go turbo in the future.