Sliding Noise Underneath When Brake or Pull Off Quickly

I purchased a 2010 Quadcab Tacoma 4X4 and have had a sliding noise underneath when I brake a little hard or pull off quickly. The noise seems to be coming from underneath the vehicle almost under the driver's foot, but more to the middle.

Also, from an ergonomics stand point, the crome stepboards seem to cause more problems getting in the truck than it assist as they are level with the floor board. Is anyone familar with an aftermarket kit to lower the stepboards to make them more functional or is it better to just take them off.

Lastly, does the gas pedal and brake pedal seem too close? My shoes, and especially my hunting boots often hit the brake pedal when pressing the gas and my shoes are only size nine. Have a great day