Dude, not to be an ass, but the pitch you're trying to "sell" is even less than primitive. First and foremost, you have no idea what a balance sheet is... you think a customer comes in, you work on the car, and it's over? that's a joke... You talk about debut, yet again, how are you going to get yourself heard?
It's actually a little bit shocking that you think it's as simple as... open a shop, demand is there, done deal... if that was the case, guess what, there would be tuning shops on every street corner; but there isn't. Why?
Keep in mind, you're looking for an investor; you're not playing the lotto.
If someone lends you money, there's long term liabilities. How will you pay it back? Will there be dividend payments? If your business tanks, what then?
You have to think about all this. Based on your responses, it's not as simple as you put it. I commend your efforts man, but do your homework.