this debate is always easily confusing. so to avoid any confusion, this is what you need to know:
96-98: B20B was made with 8.8:1 CR
99-01: B20B (JDM) and B20Z (USDM) was made, both with 9.6:1 CR
if you're planning on staying N/A i would say you want the one with the higher CR. if you decide on a 99-00, B20B and B20Z are eseentially the same thing
since you only require a block, im not sure if the CR's are different due to the heads or the pistons. if the pistons and stroke at the same all years, then it really wouldn't matter which bottom end you choose