Congratulations, bnrkwest, on your REO. You will not regret that purchase. I've been using nothing but REOs since 2011, and I swear you are in for a treat. A kick won't fit in the REO.....there's just no room in there. And the spring is a very effective safety feature that absolutely works instantly if you have a short. It drops the battery away from the contact. You will get one spare spring with the rebuild kit you ordered, so there's that. Another spring or two would be handy....that's really the only part in the REO that I like to have an extra of.
All of the Rebuildable atomizers for sale on the REOs mods site work great....some are better for cloud chasing and some are better for flavor chasing. For a great all around generally great atty, I recommend the LP RM2. I have several of them and they're super little flavor attys. They are very easy to build on, and they have a ceramic deck so they don't short out if your coil accidentally touches the deck. The REOs mods forum here on ECF closed down, but all the info is still there. You should go "play" there for awhile....I especially recommend reading through the stickied threads. I am a diehard Reonaut. I have many, many, many of them....all different models, sizes, colors, etc. if you just want to really talk REO....shoot me a PM....
Jan