The "gap" and the blurriness you are getting seems very odd and shouldn't be happening...
The task bar should be across all three monitors.
It seems (as you say) your two outside screens aren't scaling things correctly or are doing the res incorrectly.
Your Acer's could well be the problem.
Can you run single screen 1680 @ 57Hz on those Acer's ?
Try the samsung on one of the sides.
... as in the objects look way bigger and closer than they are when they shift to the cxenter monitor.
I'm pretty sure this is not your problem but it is something to be aware of ...
Objects can look bigger on the outside screens ... http://www.widescreengamingforum.com/node/7185
Oh ... and welcome to the forum ... 8)