How to get the Super Multi Ball and the z7 imp?

I've got the Z7 Imp myself from buying the Deluxe version of the game and he's currently my least favorite Imp out of all of them.

I realize that his Blasters are more accurate but the single shot function doesn't appeal to me very much- maybe that opinion will change once I dedicate some time to him but half the fun of playing an Imp for me is running and jumping around the map spraying automatic fire everywhere.

As far as the Z-7 Mech is concerned I think that the Biotic Pull tractor beam is a poor substitute for the Missle Madness; it's very clearly designed to pull in plants so that you can follow up with the Zomni Blade attack and that gives the Mech two abilities designed for close quarters combat and one ability does nothing more than pull Plants into range of the second. While the Drake Mech is also close range at least you have the benefit of a frontal shield to let you get in there. For all the fuss being made about it's supposed high power it's still my least favorite Mech out of the bunch.

As far as Super Multi-Ball is concerned I only use it for the flash and for clearing out bunches of AI Plants in Graveyard Ops. I'd rather target a single high power Super Ultra Ball at a Plant and know that I'll take it out with the one hit rather than spray three 1/3 power balls knowing that at least one or more of them will probably miss. It's great if you're spraying them at groups of Plants or if you want to spread the damage out a bit but you have to count on just damaging your target(s) rather than vanquishing them unless they're damaged already. I have the same opinion of the Foot Soldier's Multi-Rocket as well- if you're firing at a stationary target anyway all you need is one full strength projectile.