Are you mechanics, 'metal-beaters' or trimmers currently employed as custom car work professionals? Are you able, financially, to make a major initial and ongoing monthly investment and to work for a year or more without any appreciable profit? If your answer to ANY of these questions is NO, DON"T DO IT!!! I have been in the Automotive Parts and Service sector for 40 years, and know whereof I speak. There is little room in this trade for new businesses even at the best of times, and these are far from those times.
Are you or your son qualified to handle the customer service, purchasing and accounting aspects of this business, or is a third person going to be needed? Also, if you are both employed elsewhere on a full-time basis, who will do the work for the new business? You will have difficulty securing and maintaining a customer-base without giving consistent and constant attention to them, their vehicles, and their idiosyncrasies. Dealing successfully with the automotive customer requires special diplomatic skills, and at least one of you, preferably both, has considerable automotive customer service experience.
Contact your local SCORE office.
Put together a realistic business plan, and continuously update it as conditions change, but stick with the plan.
Remember the one fundamental to a successful business-no, two, no, three:
1-Find a need in the marketplace and fill it.
2-Work hard. make it your obsession.
3-Do what you love, and you will never work a day in your life.
If you have the understanding and strength to do that DO IT ! =)
Sounds good to me. What's holding you back from doing that?