Comments... Well yeah...
You were surprised it lacked low end grunt. The S/C doesn't make any appreciable boost until well beyond low and midrange rpm levels. Therefore it's no different then a non S/C'd car of the same mods until that point.
Personally I'm dissatisfied with 100% of Vortech's POS kit myself and I don't even own one.
The 3L is definitely a kick in the pants mods. Significant low and mid range power increase with slightly less gains up top "comparably"
A Turbo is just fat with power everywhere. The T28 in the kit is all done by 6500rpm (I.E. great power under the curve!) so you don't have to rev the piss out of the engine just to make some power.