You friends will make excuses not to come over any more. You finances will be depleted and your yard will grow tall with weeds. You will travel great distances to race with people in cars just like the ones you could have raced with at home. You will accumulate stockpiles of strangely distorted, tube looking things. Auto racing is an inherently dangerous sport.
Participation can result in great bodily injury, even death.
Maybe some of the information on these pages can help you to make informed decisions and help you protect yourself and your loved ones.