I just go where my heart tells me, where my gut tells me to go, where I'm enjoying my life the most, where I feel like I can have the most success. I've truly enjoyed my experience in NASCAR, to the point that I want to do it full time.

This quote is saying that person’s decision making process is based on his/her feelings and emotions. They will go wherever their heart and gut tell them to go, and wherever they feel that they can have the most success and enjoy their life the most. Ultimately, this person has enjoyed their experience in NASCAR so much that they want to do it full-time.