I think the part about the Vortec blower making less torque than
the HKS is pure myth, maybe even sales pitch by the guys selling
those blowers. I just downloaded a bunch of files from the Dyno
Database (
www.bmwdynodatabase.com) and when you compare the same
boost and same octane, the Vortec has far more torque than the HKS
blowers. Down low where it really counts, the Vortec has as much
as 40ft/lbs more torque than either of those kits. The only way I
could get the graphs to show more torque on the HKS blowers than
the Vortec, was to compare against cars with 1.5-2.0 PSI less
boost.
It was hard to get an apples-apples comparison with the ASA blower
since there's only one entry in the DynoDB for this type of
blower. From what I saw, the ASA might have more torque than the
Vortec up to a point. But just like the HKS, the ASA blower dyno
chart showed it falling apart above 7000 RPMs. The power dropped
like a rock at that point.
I'll send links to the Dyno DB files I used in case anybody wants
to do their own analysis.