I bought my ZHP in December for $10k. I am a BMW mechanic on the side and had been maintaining it for three years prior to buying it. Even though I put all new brakes, cooling system, VANOS, and OFHG on it before buying it I still have spent $1770 on it in 7 months. That means I have been spending $250 a month just on maintenance items and I do ALL MY OWN WORK! And I still have another $1500 or so to go (clutch, motor mounts, control arms, DISA, 02 sensors, the list continues) before it will be "good" for a while.
My point, a used E46 is expensive to PROPERLY maintain. Sure, you can let stuff go, but then the ride quality and reliability suck. Just make sure you get a GOOD used one.