I can't see a Vigilante being inefficient at that power level. I had under 10% slip running 10.8's@125. The car would pick up 29mph in the last 1/8 uunlocked. We have used 0 pump Vigilante's in 12sec to 9 sec cars, with no complaints, they work great. It is the converter I recommend to anyone wanting to keep lock up and run down into the 10's.
We need alot more info, old times/mph vs. new times/mph, boost, timing, O2's,etc. Just because you open the hood and dump in a bucket of $, doesn't mean it will instantly go faster.