I'll have to agree with all thats been said as well. They are a different class of car but of course you have to pay for it. I'm talking strictly money terms, doesn't matter how good it makes you feel if you cant afford it then it's not a very good idea to get one.
When I had the GT 'back in the day' I used to just drive it for the sake of it, could drive it about all weekend and on a night and wouldnt think about it.
But with the Evo you have to consider alot more if you're on a tighter budget;
How much fuel is it using? If you go 'cruising' about you could easy dust off a tank in a night, specially when you're using the loud pedal alot, 3 or 4 tanks a week at £60 a pop?
Dreaded servicing, I don't do that many miles on mine so I don't mind the cost and regular-ness of servicing but others might. I've just had the 45k service done by a specialist, which you will need to visit if you want to keep a decent service history, and it was £500+. Yes this was a big service but it will still have to be done at some point in the cars lifetime so you'll have to make sure you have the spare cash for it.
If you're not that bothered about service history then you should be prepared to make a loss come selling time, because most buyers, including myself wont touch these cars without a full history to back it up. They are designed to be driven hard and without regular treatment they wont last too long.
Wear and tear on the car, brakes for example aren't cheap, 325mm IIRC discs and pads on the front will cost you a fair penny and will need replacing fairly often if you hoon about the place alot.
With a car with this much grip the tyres need replacing nearly as much as it needs servicing, bare in mind that a decent set of tyres is gonna cost you nearly 500 notes every 7-10k.
Upgrades - I was astounded at the price of some modded parts for the Evo, everything that has the words Evolution or RalliArt on has three times the pricetag of other things. so if you want to upgrade bits, again be prepaired to pay over the odds.
And tallent... Have you got the skills to be able to drive one quickley? I know I'm not a good enough driver to get the most out of it, far from it, but I know I'm good enough to drive it failry hard and get away with it.
Me and Dan have both had some scary moments in ours. You might think just because they are a 4WD rally car with SAYC that you can't crash them, you still have to be very careful when driving hard, you cant just nail it round every corner and expect it to come out the other side. They have alot of power going to the rear wheels and therefor have the ability to oversteer without giving you much notice. Thinking about it they lead you into a false sence of security, there is that much grip in them that there is no notice whatsoever when they ara bout to go, maybe im not good enough to notice, but they feel so sturdy that you can get over confident in them and push it a bit too far...
Worth thinking about.