Want to upgrade

The best upgrades you can start with is an exhaust, air filter, change your gearing, and upgrade your reeds. If you were to Port and Polish it that would help too.
 
Like everybody else says you can get a full exhaust setup, reeds, reed spacer, airfilter, change sprockets, and send your topend to FLOTEK PERFORMANCE and get it ported for around $150. These are your cheapest options.