safe to keep downpipe loose?

hey guys, im thinking about getting a smoke stack kit from black cloud diesel..i was going to delete the cat and muffler.today i untighend the downpipe bolts to see if i would like the sound. At idle it sounds stock, but idk if that is because some of the noise is still going through the cat and muffler, when i drive it, the truck sounds awesome around 2500 RMP and up. Is it safe to leave the downpipe unbolted from the rest of the exhaust or should i tie it back up to the exhaust untill i get my kit?

Thanks alot, Jay