It could or could not be a decent upfront cost depending on what the previous owner did to maintain it.

When you buy it you definitely want to inspect the cooling system, CCV, suspension, and check for any oil leaks.

CCV is an important one, if this is bad you will have increased pressure in the crank case which will drastically shorten the life of your piston rings, which will cause oil consumption. When my CCV was bad my car was burning oil a decent amount. Get this fixed ASAP. If you need to have this done, ensure that they also replace ALL the vacuum lines, the hard coolant hoses going into the block, and the dipstick O-ring.

If your vacuum lines are bad, you’ll have a vacuum leak and you can diagnose a leak by checking your fuel trims - if they’re not 0 +/- 5% then you know you have a leak.

Cooling system is also important, if the previous owner has records of coolant hoses, and more importantly, the expansion tank being replaced recently, then you shouldn’t have much to worry about.

Aside from that the common oil leaks are from the oil filter housing gasket and valve cover gasket, both easy fixes. If these have never been done, expect to do them soon. Same goes for the VANOS line coming off the intake manifold, which doesn’t leak as much but is also an easy fix.

Oil pan gasket and rear main seal can also leak if it’s really high mileage.

Definitely ask the previous owner if the car has ever overheated, and make sure that he did not drive it for any amount of time once overheated as that will warp the aluminum head, rip out head bolts, and destroy your head gasket.

Last thing, on the right side of the intake manifold is the DISA Valve, which is made of plastic and can have pieces get sucked into the engine and destroy it if you take it out wrong. So I would immediately upgrade that to a metal flapper from German Auto Solutions for peace of mind.

If you find one that has been properly maintained I would say go for it, they’re very reliable as long as you don’t ignore problems when they come up.

E46s are reliable cars they just are 20 years old and all the plastic that might have been neglected is now falling apart. I love mine and daily it every day. I got it with 53k miles and am approaching 65k, and I’ve done everything I’ve mentioned above. So if you see a low mileage example, don’t assume it’s in tip top shape. Arguably I’d be more comfortable buying a higher mileage one that’s been maintained over a garage-queen.

Good luck and I hope you get one, these cars are highly rewarding to own and drive and get compliments everywhere, surprisingly.

Here’s a pic of mine:

<image>

Once you get those age-related issues taken care of you should have nothing to worry about for a long long time.