well i not qualified but have read in mags n such i can add few bhp and more with a remap n panel filter, have heard it can be done by hand but its recomended to have the adjustable cam gears only one is changerable the exhast side i think, ur also need the cam locking tool,
some people are recomending light weight billet wheels n runners, or underdrive kits as well for better engine response, (dont know if the underdrive will affect battery charge at low revs)
let us know how u get on