Downshifting will help the acceleration, but getting off the line is the most important part. You need to know just the right amount of power to give it before GO so you don't sit and spin.
I have used the downshift method before with no tranny issued. Don't preload too much or it can hurt your trq con. I also would recommend shifting before 6000rpm.
Or, forget the race and just post a vid of you pulling the vette all around the lot.