Weight reduction could get you that 12... even just as little as getting rid of spare and jack, sub box, not running with a full tank of gas etc. No need to take to the poor car with tools and do things like rear seat, carpet, sound deadener etc.
I know how frustrating that .077 is. I ran a 14.077 with full tank of gas (that is a 50kg weight penalty in a R33) and 10kg sub in the back seat. Could have been a "13" with a little more planning.
Other than that... MORE BOOST!
sorry, just had to be the first to say that.