Search on any of the suspension sites (can't think of names right now but if you just google "wrx suspension" a ton will come up) for 08-14 WRX coilovers, or 08-16 Impreza, those should all fit.
They're incredibly expensive though and just buying some king springs would probably be a better idea, the non-WRX is just so slow it's hardly worth it to put tons of money into the suspension. But of course that decision is up to you, if you feel like it's worth it definitely go for it.
As far as specific brands I'm not sure, someone else on here probably does though.