Pep Boys (NYSE:PBY) wasn't looking so peppy after its latest results, but investors who expected the auto-parts rust to carry over into the quarterly results for Monro Muffler Brake (NASDAQ:MNRO) will be surprised. Monro's fourth-quarter results were stylin' and profilin' -- far from a rusty bucket.

Revenues from the quarter accelerated 21% to $81.1 million. The company attributed its double-digit revenue growth to same-store sales that increased 4.5% vs. the same period a year ago. More specifically, it highlighted the growth in its oil-change and tire services, at 7% and 12%, respectively.

Shareholders have to like the purring sound of Monro Muffler Brake's sales growth, but they would also want to see that margins have remained intact. Have no fear -- profit margins are running smoothly. Despite expenses associated with Sarbanes-Oxley compliance, operating margins improved slightly year over year to 6.3%, from 6%. The company said higher selling prices were a source of its strengthening margins.

Let's see, so Monro Muffler Brake raises prices but still grows sales by 21%. If only it were that easy for every company. Monro credits its winning strategy of offering attractively priced oil changes for increasing customer traffic. And more cars in the shop means there's a greater likelihood of an owner choosing to have a higher-margin service completed for his or her vehicle.

The company's strategy is working, as its net income jumped 35.9% to $2.8 million, or $0.19 per share. This brings its year-end EPS to $1.35 for fiscal 2005. Looking to fiscal 2006, Monro Muffler Brake expects its EPS to be $1.52 to $1.60.

A current-year price-to-earnings ratio of 17 may sound like a good deal when you look back at the 21% revenue and 36% earnings growth for the latest quarter. However, for the new year, the company expects its earnings and sales to grow at a blended rate of 14%. Measured against this rate, Monro Muffler Brake's stock appears to carry a reasonable valuation -- but is far from a discount.

Monro Muffler Brake has been stepping on the accelerator lately, but investors might want to be careful.

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Fool contributor Jeremy MacNealy does not own shares in any of the companies mentioned.