If your system has been set up to a threshold level of accuracy and retail resolution, then removal of the grills will definitely improve things enough that you will want to take them off. I am still using a pair of Snell B Type full-range 5-sided speakers since 1993 and have tried them on and off in my system as it evolved. I never was able to hear a difference until this year when I finally got the message about isolation platforms for every component and power supply and proper cable separation. Only after giving every component its own maple platform sitting on iso-blocks and an assortment of brass footers, Terra Stones, Herbie's Rollers, etc. gleaned from the used market, was I able to actually hear more detail when the covers were off and to crave it when they are on. Until you address the system set-up issues that lower the noise floor that interferes with the low-level details, the difference might be inaudible to you as it was for me until I finally got my system to basic fundamental audio set-up integrity.
