This is my favorite kind if you dont mind the price.
http://www.amp-research.com/products/truckaccessories/powerstep/
but if you never go off road look for a set of takeoff OEM's
2015 GMC Sierra 2500hd 6.0 w/4:10 rear end
2006 SkyLine Weekender 180
1200/12000 Equal-i-zer WDH