Well I'm gonna look into purchasing a wideband. I've always been scared to play with the fuel and timing myself. Maybe the wideband will give me some courage..
Are there any disadvantages to ebrake launches?
Yea, you can bend and break parts on the rear brakes. I personally would NOT do this.
I have since swapped to a vacuum setup (stupid powerbastard

I have a D5 converter and went a best of 11.94 I suspect it may be re-stalled though. Don't know for sure though. Drivetrain was fresh when I bought my car.