While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of 3D Systems Corporation (DDD -2.84%) sank 5% today after Bank of America downgraded the three-dimensional printing technologist from buy to underperform.

So what: Along with the two-notch downgrade, analyst Wamsi Mohan lowered his price target to $65 (from $95), representing about 20% worth of downside to Friday's close. While growth investors might be attracted to 3D Systems' top-line trajectory in recent years, Mohan thinks that Mr. Market is currently overlooking the competitive and execution risks surrounding its long-term profitability.

Now what: B of A sees plenty of growing pains ahead for 3D Systems. "(1) Organic growth rate peaking in 2014 and incremental topline growth will come at the expense of margins, (2) We view the increased investments as a catchup in spend necessary to stay competitive rather than driving incremental growth, (3) A lot of the M&A while additive to near term growth, in our opinion, will result in diluting LT organic growth and adds integration and execution risk in the interim, (4) A lot of high profile partnerships sound exciting (Motorola Mobility, Hasbro, Hershey's etc.) but success will be predicated on widespread adoption and margin performance driven by such ventures will likely be challenged," noted Mohan.

Of course, with the stock now off more than 20% from its 52-week highs, those concerns might be offering tech-savvy growth investors with an attractive entry point.