I recently bought a 2000 pontiac GTP 4 door dark blue with tan leather interior. 88,000 miles. its got the supercharged v6 obviously. fairly fast car but i have plans on modding the pulleys, intake, exhaust and somwhere down the line, headers. any tips on what i should mod first and how it should be done. like say i mod my pulleys, should i have to also upgrade my head gasket?