Need input on new speakers

I personally am a fan of KEF speakers. They are very clean sounding with excellent reproduction capabilities.  The "Q' line is their lower end but blow blow away speakers 2 and 3 times their price. As they just released a new series of "Q"  speakers many of the previous line are on sale directly from KEF. Crutchfield, Amazon & Best Buy have them for the same price with free shipping. The Q 350 is a Stand speaker that consistently gets excellent reviews. Their tower speakers are the 550, 750 & 950. If you can spring for 950's go for it. I have the 550s with a KEF Kube 10" sub. You really won't need a sub with the 750s & the 950s sound like you are in a concert hall. 

I also think the higher end lines of POLK are great sounding speakers for the price, but all things being equal the KEFs are audiophile quality and a great bargain at the reduced prices.

I have owned multiple KEF models. I'm currently enjoying the new Q Concerto Metas. They are very solid for rock music, with a very warm and robust bass - especially when coupled with a subwoofer.

That said, for the OP's needs I second the recommendation for Zu ahead of anything by KEF. Both the DWX and DW6 would be perfect for the OP's setup, and I can attest that they most definitely will rock. The DWX would probably be ideal. Have heard these speakers in several settings and they are like modern-day Cerwin-Vegas. Super easy to drive, powerful bass, and they will crank. Sound good, too.

When I demoed the KEF LS50 (before meta), I also demoed the KEF R700 floorstander which sounded similar but with bass extension. So maybe a used KEF R700 here .  
 

I demoed multiple Zu but it never resonated with me- from the many forum comments, seems few resonates with its sonics so is highly subjective.  Zu is typically highly efficient so caters more to those with lower amp power.