i'd take a legnum over a stagea, and no that's not because i own a legnum, i've pretty much owned both (my ex gf had a modifed stagea)
they have such a smooth torquey V6, AYC is a fantastic system, the interiors are quite nice (mine has factory recaro's and carbon fibre) fuel economy is very similar between the 2 cars, its possible to get 10L/100km out of either if driven normally.
best idea is to decide what you want from it, and take both from a test drive.
if a relatively stock, quick wagon is what you want, go the leggy, if you want to mod the shit out of it and chuck a stroker in it, go the stagea...
last time i went to the drags, i had a 3" catback, and 12psi... vs. a S2 stag with 12psi, safc, fmic, pod, exhaust.. (basic RB25 mods)
i did a 13.76, and the stag did mid 14's..
i did destroy an auto gearbox at the drags too, however i'm about to do a manual conversion in a mates leggy, and he has been trying for a month non stop to kill his current auto, and it WILL NOT die, limiter in neutral into drive, etc etc... it just comes down to the service history.
here's my super vr-4.