I have a 97 SSEi stock with 70K miles. I have a K&N filter installed but I'm looking for cheap upgrades to boost HP. I was looking at new headers, exhaust, etc. All suggestions are welcome.

A smaller supercharger pulley is usually the cheapest way to get hp out of the supercharged engines.

Pulley is definitely one of the cheapest. I would probably do the exhaust and pulley with the K&N that you already have done. Headers are pretty expensive so you could do the exhaust and pulley a lot cheaper. I got my pulley from www.3800performance.com. For exhaust it is cheaper to find a reputable muffler shop and have them do a custom setup. I just took the muffler and tips in I wanted and they did all the bending and mounting for $100.