Thinking I need a Sub...

I agree with Karl_desch, so upgrade your speakers if you must improve your bass. There's a reason you must spend considerable bucks for a true full range. As Karl put it, "coherent balanced sound." Adding a sub may give you the low frequency you crave, but you may not get a perfectly smooth sound. If you can still find a high-end dealer with a store out there, try listening to a quality restricted LF speaker with a sub, and then listen to that brands full range entry as a comparison.

Johnnyb53,

Personally, so with my ears, subs have always sounded strangely additive, but they may not have been set up properly. Or, maybe they were'nt matched correctly. So, my listening winners have consistently been coherent full range speakers. Recently, there has been one exception, and that was the Volti/Border Patrol room at RMAF 2013. The sub, was simply not there, so I was not aware of its presence, so coherent.

Regarding, "Going full range "may not get a perfectly smooth sound" either..." I completely agree with you. Not all full range speakers are created equal. This is why my advice was to listen to the different setups within the same brand of speakers. So, compare for yourself and pick your own preference. Not the easiest thing to do, but the only way I trust to evaluate.