Yup ^^^...SP gets all bent out of shape when people advertise for less than the MAP...heard they completely shut a couple of businesses off because of it!
That blue and black looks familiar. Wonder where I've seen it before? Oh, wait!
DON'T USE CO2 WITH A SHOCKER OR A PM!!!!!! I DON'T CARE IF MOSES HIMSELF COMES TO YOUR HOUSE WITH A SHOCKER IN ONE HAND AND A CO2 TANK IN THE OTHER!!! STEP AWAY FROM THE CO2 BOTTLE!!!!
Yes, you can use Co2 on a shocker so long as it's antisyphoned, some guy over at Shockerowners.com did it, but even if with A/S, you're taking a big chance. No need to even risk it...
As far as which one, that's purely an opinion decision. You really need to shoot both before you get them to decide.