Is the Zex kit as safe as they say it is? If I have someone that knows what they're doing install it and I just leave it as is, should I be okay? I just can't live with it anymore...I raced my girl who was driving her Tahoe and that bitch had the nerve to tell me my car wasn't fast!!! It isn't....but still....the nerve...good thing she put out later !!!!! So I really want to get the Zex kit and just want to make sure it would be my best bet as a noob!!