What: Shares of auto parts retailer Advance Auto Parts (NYSE:AAP) surged as much as 11.8% today after its quarterly results and full-year outlook topped Wall Street expectations.

So what: Advanced Auto shares have been fueled recently by its July inclusion into the S&P 500, and today's bottom-line beat -- Q2 adjusted EPS of $2.27 versus the consensus of $2.25 -- coupled with solid full-year guidance should only draw more positive attention to the company. Advance Auto is still in the process of digesting its January 2014 purchase of General Parts International, so while Q2 revenue of $2.37 billion slightly missed estimates, improved margins during the quarter suggest that the integration remains right on track.

Now what: Management maintained its full-year EPS guidance of $8.10 to $8.30, versus the average analyst estimate of $8.25. "Our teams once again delivered on our synergy expectations, expanded our core gross margins and demonstrated expense discipline to grow our Comparable Operating Income 8.7% in the quarter," said Vice President and CFO Mike Norona. "We continue to stay focused on our base business while meeting our integration milestones and remain on pace to deliver against our full-year guidance." Of course, with Advance Auto shares up more than 50% from their 52-week lows and trading at a 20-plus forward P/E, much of that guidance might already be baked well into the valuation.