Whatever is said if you have diesel, common rail and it has an EGR then the catch can is most important, mine collects about 250ml of oil every 10,000km' I dump it when I service the engine (10K) , this oil would otherwise go into the combustion chamber as hot oily air which in itself is not a drama BUT when mixed with the Dry, Sooty exhaust from the EGR system it mixes in the manifold and turns into a gooey tar which in time will slowly choke your engine, looks like those anti smoking adds with the tar filled lungs ..................Having seen the insides of manifolds and helped to clean them, fit a catch can......................... fitting one won't cause any warranty break downs but not having one could........Since I'm unable to shut down the EGR valve on mine the manifold is coated with dry soot which I clean out every so often with some spray stuff, could shut down the EGR but not going for a remap or anything.
I would go the Provent Unit for the Colorado then you can drain it easy enough without removal, fitted my can where the horn used to live.
Toyota's are so good and reliable that they only change the fuel filter when the dash light comes on, fat lot of good if your back of Bourke or somewhere and it stops, warranty servicing isn't all its cracked up to be ....