5 things that will help your launch -
LSD
Drag tires
Motor Mounts
Traction Bar (best off with jimfab.com)

-Practice - what are you launching at.

Those 4 things are in price order i believe - depends where you buy from ofcourse. LSD will help tremendously - make sure you decide what KIND tho ... there are 2 main types.

Since you have the tires and perhaps no money for the lsd - i would do traction bar then mounts.