14/4 wire for speakers- good idea? Bad idea?

Is it Canare 'star quad'?

That stuff always worked well for big bar installs. Used to buy it by the roll....

It's not a bad idea.. 

What you'll find with cables is that the materials and geometry can make a big difference. 

So, there's a good possibility you'll hear differences using different cables. Whether or not it's an improvement depends on all the other parts of your system.

If you'd like to experiment somewhat cheaply, DIY is a great way to start without dropping loads of cash. Here's a good resource: http://www.image99.net/blog/files/be8de0c383c5434907610d6b55049e69-75.html

DIY is great for isolation as well. I use springs from Grainger under my components for isolation.

I use that for my surrounds, side and rear. I would use a larger gauge wire for the front speakers. Don't know how far they are positioned from your amp, So 12 or even 10 Ga.might be better.