leave TCS on, hold the NOS button on the launch and just go WOT all the way. Make sure you have racing slicks super soft. I'm trying to hit the 7.9 secs range.
It depends on the shifts if your over reving or short shifting and hes getting perfect shifts that could be the problem my wrx runs 8.4's the fastest i got was 7.8 (miracle)
Are you both using automatics, or manuals, maybe he's using a different transmission than you are. What are your 1000m times like? he may just be using shorter gears than you are.