Of quirks, our cars have plenty. The best thing you'd have going for you is that the 2004 models seem to tend to be more reliable than the 02 and 03 models.
There was a good post I personally read back when I was browsing here to decide if I wanted to buy my 04 SVT (I did, and have yet to regret it), I'm having trouble finding it tho. It was a huge thread of things people both liked and disliked about the cars, which showed up both reliability issues and other quirks or oversights.
To give you the short list, if you hear a rattling noise from the engine bay when you let up on the clutch at a stop, you need a new clutch and flywheel, which may or may not be covered under warranty.
DSI, the dual stage intake runners, switch over at 5000rpm. Under heavy throttle you should be able to hear the transition in the engine/exhaust tone. If you dont, and if the engine feels sluggish at low engine speeds, the cable that actuates the DSI motor is probably broken, which is kind of a pain to replace.
There havent many problems with the Getrag 6 speed that I've heard of, its operation is stiff, this is normal.
Another big gripe is the factory ECU software, the 2004 came with ZED0, which was better than both RLA6 and YRF0. I've never driven an earlier year, but apparently it was bad. If you want a fair measure of the car's performance, dont drive it hard until the engine oil temp needle (far right) is horizontal. By then the car will be up to temp, and mine has never run right cold, aftermarket tune or not.
I cant think of any other major mechanical faults you could look out for. Apparently a leanout in cylinder 3 burns a hole in that piston from time to time, but its been a while since I heard of that happening to anyone.
Enjoy the drive, post back with your reactions.