bbk header tuning?

i just installed bbk longtube headers with the bbk catted x-pipe on my 2001 mustang gt and heard that i need to tune it to get its full potential. i have the SCT X3 tuner and was wondering what code i need to type in. Also when i rev the motor theres a noise that sounds like ticking when i let off the gas, is that just the sound the header and x-pipe make?