On the day of GTRZILLAR32's e46 M3 test drive. May we all one day drive flawless BMWs...
I bought an e46 coupe (from a dealer) that I ended up losing a ton of money on. All the advice here is spot on. Make sure you check everything. Do the two front windows go smoothly down and up? Do the motors in the pop-out rear windows work flawlessly? Check the trim around the doors. Mine was basically just holding on by a couple threads of cheap glue. I didn't notice it because it was on the passenger side! I noticed a gash in the alloy wheel later. A couple months later I found out that the spare tire was flat. Of course this happened on the side of the interstate during morning rush hour. The first tow truck wouldn't do it and they had to call in a flatbed. The ABS light would come on for 15 seconds when you started the car and then blink out, but hey, I didn't know the dash lighting sequence on a car I'd never driven AND there was so much more to look at! This was a BMW! 5 speed! sport package! topaz blue! It could be mine with creative financing! Within months (although possibly on the test drive as I was distracted) The oil pressure light would go out after starting the car and then come back on for 30 seconds before disappearing again. The E-Brake light would occasionally stay on regardless of what position the brake was in. Sometimes even the ABS light would join it in solidarity.
Still, it was my BMW and it was AWESOME. It was the first car I would start getting excited to drive while getting ready for bed the night before. I didn't believe any of the non-sense about it attracting "chicks" or getting treated better because people might think you have money. And none of that happened. E46 are great cars. Make sure you get an independent inspection and don't be afraid to walk away. There's still plenty of these out there and you will get yours someday (even the dealers know that). Don't get too emotionally attached to this one before you even drive it, don't let the dealers and sales managers fuck with you. Point out everything you notice wrong, and say you won't give them a dime for this car until they fix it. Always make it extremely well known that are willing to walk if you don't get everything your way.
If this car is the one: Congratulations! You bought a car most of us OPPOs dream about. But if you have any doubt about anything, let it go. You will find the one! GOOD LUCK!