If you want 125 TAG and 100cc in Orange County, I highly recommend MDG karting in Orange. Stu is helpful and offers great karting advice, especially for a someone new in karting. He has everything , especially for 100cc. I know that he can pretty much get you anything you need in karting. I have known him for a long time; ever since his shop was in the old location.
The shop has a nice showroom with easy parking. I love going there! I heard that his son, Kyle is a great coach.
For shifter kart racing, I would definitely recommend MRC in Corona. Willy and Billy’s vast knowledge and their willingness to help us have been so awesome. They have a very professional setup with a complete inventory of shifter karts and parts. They are always at the track testing , and that helps a lot with on-track parts and tuning support.
I truly believe that both of these shops mentioned have business models that are highly customer driven and not money driven. The owners are truly passionate about karting.