Will a high quality preamp really make a difference in sound?? Also speaker cable

My speakers are B&W 706s3 bookshelf speakers. Yes they are a bit on the bright side.

Another question fellas...if I were to throw a separate standalone dac into the mix, would it go between the NAD and the Cambridge audio streamer?? Little confused on this. As always thank you for all the advice in advance. 

Or would it go between my laptop and the NAD or the Cambridge? 

You could bi-wire with these and they’re a screaming bargain and may help tame brightness a bit as well. Hurry, at this price they won’t last long.

https://www.usaudiomart.com/details/650194860-acoustic-zen-satori-shotgun-biwired-speaker-cables/

The DAC would go between the streamer and the NAD. 

@malatu,

He wasn’t that  wise, a blowhard was more like it. So happy he is gone, his smugness grated on me.