Really depends on your budget. If it's low... Being carb not injected, you can still benefit from an upgraded air filter. As a no cost mod too, the 4AF has an additional plastic snorkle attached to the steel snorkle, you can remove the plastic addition and it shortens your intake tract. You can fit an exhaust, just be careful with the size, No bigger than 2" I would say and stay away from 'canons' Being a 1.6L they will only sap your torque and give you noise but now extra power. You won't find too much info here because most members have the newer models, but you can check out toymods.org and twincam.org and you'll find lots of 4AF info and help.