RE: tires keep blowing up, need help
No probs dude. Not only will this reduce front wheelspin and ballooning a lot, it will allow you to put more power to the ground. I don't know if you could before, but after doing this you will be able to do standing backflips and long wheelies and stuff like that.
Also, now with a 21 tooth pinion, and now that you will not be bleeding a lot of power through the center diff, your car is going to be a LOT punchier and your motor will get a lot hotter. You may find you have to stop sometimes to avoid overheating. If you are placing an order for diff oil or anything else right now, consider getting a small temperature gun at the same time if you don't already have one. Don't let the motor go over 180-190F. 21 teeth is a lot. If you find the motor is getting too hot, you might want to go to an 18t or something and see how that goes.