If you can afford the running costs then go for it, you wont regret it!
The biggest difference you will notice between a hot hatch and a car like the Impreza is that you dont need to rag the ass off the impreza to do anything, where as with a hot hatch you will.
The PPP will give you better feel, my old car was at 249bhp, enough for most people, on the road you have more flexability than alot of cars out there, above 100 and your leaving pretty much everything behind.
Service costs are quite high though, 6 month intervals/7.5k miles whichever is first, reliability is very good, dont buy a neglected car though, it will cost you an arm and a leg to get it sorted.
I had my MY00 PPPd turbo for 3.5 years, great car! but alas, now sold.....
And replaced with another impreza but a little more hard core ;-)
Tony