In this current tough stock market, it pays to play defense with value-oriented stocks. But you should always make sure you have exposure to the more dynamic investment opportunities as well by holding at least a few names that carry major upside potential.

Taking this approach, I selected four stocks that qualify as “swing-for-the-fences” investments. They carry risk, but could also help power up your portfolio, despite the broader market’s travails.

Here they are…

#-ad_banner-#1. Exide Technologies (NYSE: XIDE)
I’ve been impressed with the far-reaching turnaround efforts of this car battery maker, yet shares always seemed a bit too pricey in relation to near-term cash flow prospects. This is not the case anymore. After a 40% pullback and a still-bright outlook, shares now look set to deliver 100% gains for those with a two to three-year time horizon.

Exide first came up on my screen in February 2010, when the company ended a supply relationship with Wal-Mart (NYSE: WMT). It’s tough to lose a key customer, but management swallowed its medicine by foregoing ample revenue that carries low profit margins. That’s the cost of doing business with Wal-Mart, so management wanted out. Exide posted negative gross margins in fiscal 2009 and fiscal 2010, and vowed to do better in the following fiscal year.

Gross margins indeed rose back up above 7% in fiscal 2011, helping to push operating profits up to $138 million (prior to restructuring charges) — the best showing in seven years. In addition, the company more than made up for the lost Wal-Mart business, eking out a 7% sales gain.

So why are shares coming under pressure? Because management recently decided to focus on customer relationships by temporarily absorbing big increases in the cost of lead, a key component in batteries. Exide will have to pass on these cost increases to customers in coming months, but wanted to give them time to adjust. “For the most part, we held pricing steady in the face of rising commodity and fuel costs with the intent of securing new volume,” noted CEO James Bolch in a company press release.

Looking ahead, management expects the eventual price hikes, coupled with a few new customer wins to push operating income at least 25% higher in fiscal (March) 2012 to a range of $160 to $170 million. Going one step further, rising sales of new vehicles (which are expected to grow at a 10% clip for the next few years, according to Goldman Sachs), coupled with replacement batteries from an aging fleet of existing vehicles, could push sales up 10% in fiscal 2013 and operating income to about $200 million.

Exide’s market value currently stands at about $575 million. But as the company’s turnaround continues, I expect shares to trade up to about six times my projected fiscal 2013 operating income target. This would value the company at about $1.3 billion (or $15 a share), roughly twice the current price. This multiple won’t arrive this year, so patience will be required.

2. Assured Guaranty (NYSE: AGO)
I ran through my investment thesis for this municipal-bond insurer back in April.

Since then, an increasing number of states finally appear to be making real headway with their operating deficits. Therefore, the chances of a major bond default at the state or local level are starting to recede. Shares still trade for about five times projected 2012 profits of about $3 a share, even though the company’s real earnings power is likely to move back up to the $4 to $5 range when the economy rebounds. My bullish profit view stems from the fact that Assured Guaranty now faces a lot less competition and should have real pricing power for its bond insurance going forward.

But forget my bullish profit view and focus on Assured Guaranty’s book value instead. Current book value now stands at $27 a share with the possibility to hit $30 by the end of 2012 if present trends continue. Look for shares to trade up from a current $15 to book value by then — a 100% gain — once concerns about the possibility of state or local municipal-bond defaults have completely gone away.

3. Monster Worldwide (NYSE: MWW)
It’s tough to be thinking about employment stocks when monthly job data has just cooled off. This is why shares of Monster Worldwide have been crumbling in recent sessions to just $13, a nine-month low. Yet if you believe the United States will avoid recession and employment trends will start to recover later in 2011 and into 2012, then shares of Monster Worldwide could be the best play on this theme, a topic I discussed in more detail in February.

Back then, I encouraged investors to focus on the prospects for $300 million in earnings before interest, taxes, depreciation and amortization (EBITDA) by next year. But I’m now looking at where this stock may go in a year or two. Projected 2013 EBITDA could approach $350 million. If that’s the case and shares garner a multiple of 10 times that figure within a year or two, then you’re looking at a stock approaching $30 a share, well above the current $13 price.

4. Winnebago (NYSE: WGO)
This looks like a tough stock to own this year. Gasoline prices remain too high and consumer spending remains too weak. Yet this is precisely the time to be looking at “out-of-favor” stocks such as Winnebago, whose shares have dropped from $16.50 to $10.50 in the past four months. In the middle of the last decade, shares routinely traded above $30.

To find this stock appealing, you have to assume the broader U.S. economy will get back on a steady growth path in a year or two. If that happens, then the ever-rising tide of aging baby boomers would create a powerful base of customers for Winnebago. The company earned an average of $1.65 a share from fiscal (August) 2004 through August 2007. If per-share profits simply rebound back to $1 a share in fiscal 2013, then investors will start to push up the multiple to about 20 times projected profits in anticipation of further profit gains in subsequent years. This would push the $10.50 stock north of $20.

Action to Take –> To bag a double, each of these companies needs a better economy. The outlook for 2011 remains pretty dismal, but an improving position in 2012 and 2013 would help these companies see rising profits and a rising multiples, leading to higher share prices.

P.S. — Few investors realize that a 20-year energy agreement between the United States and Russia is about to expire. This deal supplies 10% of America’s electricity. As broke as our government is, the situation is so serious that President Obama is asking for $36 billion to avert this crisis. And Republicans support him. Here’s what’s going on…