hey mate,
from what i know..
the rb20 has been around for quite a while now. started out inthe r31 in japan as an rb20 redtop NICS. then, after some development, along came the rb20 redtop ECCS version, also in the R31
the r32 came out with the rb20 silvertop ECCS version. all r32's have the rb20 silvertop version, all have a ball-bearing ceramic turbo, all are intercooled etc.
they are a great engine for modifications. now remember that they are only 2L in capacity, so when the turbo is "off boost" they lack the ability to get the car moving like a commodore would. but, after say 3000rpm, they really get moving.
on a manual car, with about 2000 spent on an exhaust, boost controller, and maybe a front-mount intercooler, they go like a cut snake.