Penny stocks can be tempting, but you don't have to go dumpster diving on Wall Street to find exciting growth-stock ideas. In fact, many of the most attractive wealth-building tickers out there are established leaders in their chosen fields with big-ticket stock prices to match.

So when we asked a few contributors to The Motley Fool to share their best growth-stock ideas, they stayed far away from the penny-stock ghetto. Read on to see why our panelists recommend adding ShotSpotter (SSTI 1.05%)Aptiv (NYSE: APTV), and NXP Semiconductors (NXPI 4.18%) to your portfolio, right here and right now.

Woman wearing glasses and a business outfit stacking piles of coins on a glass tabletop.

Image source: Getty Images.

The shot heard 'round the world

Rich Duprey (ShotSpotter): Gunshot detection specialist ShotSpotter has the chance to see sales grow exponentially as demands to curb gun violence grow. Using a unique technology that can zero in on and isolate the sound of a gunshot and then notify police of its location, ShotSpotter essentially has the market to itself.

It currently has 77 public-safety customers covering approximately 510 square miles in 88 cities across the U.S., including three of the country's 10 largest cities, as well as seven security customers covering eight college campuses.

As it signs on more customers, revenues are expanding at a torrid pace, up 52% so far in 2018, which is on top of the 53% rise last year. It's looking to turn profitable by the end of this year.

Far too often, investors seek out penny stocks that have a good story but lack a product to back it up. ShotSpotter is no penny stock (shares trade at almost $60 a share), but with a market cap of just $550 million, it is of a small enough size to attract investors looking for the next big growth opportunity. And it has a product and contracts to underpin those expectations.

Shares have already quadrupled over the past year, but like Axon Enterprise, which is cornering the market on police body cameras, ShotSpotter is positioning itself to be the national leader in default wide-area gunshot detection.

As more cities choose to deploy ShotSpotter technology, look for its stock to shoot higher still.

Take advantage of NXP's big, messy breakup

Anders Bylund (NXP Semiconductors): For the last two years, this Dutch maker of embedded microchips labored under the impression that larger rival Qualcomm (QCOM 1.41%) would close its epic buyout bid to create a global semiconductor powerhouse. But Chinese regulators dragged their feet and Qualcomm eventually threw in the towel, nixing the whole merger idea. NXP's share prices cratered on the news and have now saddled shareholders with a 23.5% drop in 2018.

That's your signal to start a position in NXP.

So the $44 billion Qualcomm deal is off the table, but the business realities that inspired the American company to launch that massive bid have not gone away. NXP remains a leader in several important markets, led by automotive computing and data security solutions. Picking up NXP shares on the cheap gives you an instant foot in the door of these important sectors.

And yes, the stock is cheap today. NXP Semiconductors is trading at 11 times forward earnings and 17.5 times trailing free cash flows -- arguably bargain-bin valuation ratios. Considering the company's leading position in some of the chip industry's most exciting long-term growth markets, it's really a no-brainer of a buy.

Oh, and don't forget that Qualcomm's failed bid triggered a $2 billion breakup fee. NXP has promised to put that to work for stock owners in a $5 billion share buyback program, which is both a shareholder-friendly move and a vote of confidence in NXP's cash-production muscle.

Look for NXP to wow investors with October's third-quarter report, which will be the first presentation of financial results since the very eve of the Qualcomm breakup. I think it's smart to lock in the current deep-discount prices, because they probably won't be around much longer.

Close-up rendering of a silver sports car zooming into the future.

Image source: Getty Images.

The future is near

Daniel Miller (Aptiv): Roughly a year ago, Delphi Automotive spun off its legacy powertrain division to be renamed Delphi Technologies, with the remaining parts of the company to double down on the future of electric vehicles and self-driving technology and be known as Aptiv. The result is a way for investors to invest in the long-term driverless-car business; it's potentially lucrative and far less risky than penny stocks.

One reason that Aptiv is a safer bet amid the many companies developing driverless vehicle technology is that it provides automakers with components and systems, such as advanced driver-assist systems (ADAS). When you invest in General Motors, you're mostly locked into whether GM wins or loses in the driverless race, but investing in Aptiv means investing in a company that can sell its products across the market to multiple competitors.

Aptiv's business isn't locked into dealing with only automakers, either, as its recent partnership with Lyft has proven. Aptiv and Lyft recently announced the partnership has completed 5,000 self-driving rides in Las Vegas. More important was the fact that the two companies charged the same price for the driverless rides as for trips handled by humans and that the project was making money.

For now, Aptiv is one of a few direct investments in the future of driverless vehicles, and it delivered record double-digit revenue growth, operating income, earnings per share, and free cash flow during the second quarter. And if its partnership with Lyft has done anything, it has shown that consumers might already be willing to let driverless cars transport them, opening the door for the lucrative market to arrive sooner rather than later.