Root desire z is S-OFF, now what ?

[docfear]

hi people, i want to root my desire Z, but i noticed it is already S-OFF, do i use the complete guide for rooting or just part of it... i got this phone used so i dont know what the other guy did on it, i read somewhere Do not Flash if phone is S-OFF...so i'm i bit mixed up here..i installed the new update 2.3...so if anyone can help me out here or point me to the right place

thanks in advance