You should probably look at importing...the ones that are here are owned by enthusiasts who, more than likely, aren't looking to sell since they went out of their way to purchase a car that was never sold in Canada.
That said things you should check:
Generally Speaking- Compression test
- Leak down test
- Boost leak test
Evo Specific- Make sure to ask what the modifications are on the car. If the owner is clueless I would walk away unless you can track down the shop and/or previous owners to know the service and modification history.
- If the car is still on the stock turbo you should hit full boost no later than 4000rpm...if it feels laggy or delayed then the turbo might be damaged.
- Make sure the car shifts cleanly in all gears. If it doesn't it could be a problem with anything from the clutch to the gearbox itself and that is a very expensive job. The 6 speed gearboxes are weaker than the 5 speed but they suck for highway cruising. It's a compromise so know what you are using the car for. I wanted a 5 speed because I plan on making a lot of power in the long run.
- Ask what fluids were used in the car. You want to make sure the proper service intervals were carried out, that oil was changed every 3000 miles. Start thinking in terms of miles as well since you are buying a car from the US. The drivetrain fluids for the transfer case and rear diff in particular are very important. DiaQueen should be used...some people use alternatives but generally speaking you want a car that used DiaQueen oil for the diff service intervals.
Evo's drink gas like no ones business...be prepared to pay out if you enjoy getting on the throttle.
If you buy a heavily modified car it could either be a blessing or a curse. Pros: you will save a lot of money in the long run: parts, shipping, tax and installation and tuning all add up. But if the car was modified poorly or the screwed up the wiring then you could end up with a pita that takes a long time to get sorted...more than likely spending lots of down time and money figuring out arbitrary issues.
They are very reliable cars once you service them at the proper intervals and change fluids regularly.