im in the process of obtaining coby extractors for mine, bought them off a guy on here. with a 2.5" catback you do loose some responsiveness in the low end, but theres heaps more go in top end power. hopefully the extractors should help even more.
not alot of other mods you can do really to get power, but yeah. get a heatshield made up for it and get them HPC'd and youl be right on.