They are the standard wheels, unsure if they are the same as any Impreza models?
As for running costs, I've been averaging 24mpg normal driving, 30mpg on a motorway trip and <10mpg if having fun. Insurance is better than an Impreza even tho higher power as standard.
It is recommended they are serviced pretty regularly but if your happy to do it yourself its no more expensive that any other car.
Bits are relatively cheap for them, I did a wheel bearing a few months ago and the bearing was £2 cheaper than a wheel bearing for a fiesta that was ordered at the same time. With the 4pots changing the pads is easier than any other car that I have done before.
Big bills come when anything needs to be done to the engine, due to being a boxer even the smallest job is an engine out scenario. I believe they are generally pretty reliable until people turn up the boost without adjusting fuelling accordingly or neglect on the servicing!