Just tell the owner that his markup is too high and other places sell for less and ask him to lower the price. Your giving the hobbyshop a chance to make the sale at the price you want. If he dosen't give you the price closer to what you want, then feel free to shop around. Small business owners can be bargained with, especially if you plan on being a local racer, let him know that, if he's a smart small business owner he'll take the consistant long term sales from you, instead of forcing you to shop somewhere else. He will have higher prices than mail order, but not much higher
Always subtly let your local hobby shop know your keeping an eye on his prices. And don't discuss the prices he gives you with other racers when you get good deals, likewise don't try to get him to lower prices in front of other customers.
At least give your local hobby shop a chance to make the sale though, even small business owners appreciate that, even a tough sale is still a sale.