i had the same concern. logic would say all you are adding is a filter basically between the pcv and intake. but if you had some kind of engine problem, would the dealer try to tie it to the mod? never say never. if i did have a serious engine issue (say the famed cams, lifter issue) i would remove the catch can before I took it in for it, just to not give them any excuse to deny me warranty. it would probably take me 15 minutes to remove it. in terms of manufacture, i bought a Moroso. a) because a member here who's opinion I trust and has a race truck has it and stands behind it b) it's a larger capacity can then some c) it has a drain valve under it. some don't. i like that i can simply turn a valve to drain it from the bottom without having to undo the bottom part of the can to dump contents. just seems like a cleaner, easier system to deal with. careful if you buy some of these off amazon as they won't come with filter medium (the steel wool sort of but not steel wool stuff. i can't remember what it's called, but you don't want to use just a steel wool pad in these! fragments could break off and get into your engine!).
