Could not agree with you any more! You know the expression too many chief and not enough indians!?! This spells failed business better than anything else. Those employees will walk all over you in no time. If you work alongside them and have an "equal" attitude they will (in their mind) think that you are equal and start expecting equal split of the profit. When they don't get it, they will walk with the attitude that they can do it all for themselves. Either that or they will have the attitude that the grass is greener on the other side.
In a service business with no official licensing, registration, or formal education etc.. you are bound to have a high turn over, as anyone can hang their own Detailing sign with very little capital investment. What will keep them around is a sense of fulfillment and a general understanding that they will never be able to survive in a competing environment. This can only be achieved through YOUR reputation. They will get fulfilled with the fact that they are working for the best in town, get the best education in town, and get a fair pay and the opportunity to work on awesome toys. In the same they will know that they will never be able to "steal" your market place (except for the crumbs falling off your plate).
On this forum you find a quite a few part-timers with an incredible reputation that anyone of us would be thrilled to spend a weekend with, they have that strong of a reputation and following....... and those guys are part-timer weekend only businesses that are booked weeks and sometimes months in advance. This is the kind of environment that will not only attract but will help retain "quality" employees. The best employee is the one that seeks you out, not the one that you coherce out of another deadend job.