I'm sorry, nobody is hitting 12s w/ just a Vortech and slicks. No way.
Mid 13s, yes, that's very possible, but you'll need a bit more than 100wheel hp to go from a 15 sec. 1/4 to a 12 sec. 1/4.
Now, add water injection, nitrous, etc....

Hmm, blown and juiced up SVT, Simon, you ready?

John