I had a "pickup pack" installed on my 2016 F-350 long bed with the slider as well. You guys aren't cheap, BUT YOU ARE THE BEST! I get compliments on my truck all the time. I use it as our RV tow vehicle and everything I need is easily accessed. Hats off to Highway Products!
They should cost just as much if not more than the chassis you're putting them on. If they don't... I'd question how long they'll last. Every company touts longevity but 90% of them wont outlast the chassis they sit on.