Hrmmmm... yea someone should have told Tiff Needel as well, especially when he went out in the new E46 M3.
The prime enemy of stock E36 M3's when trying to drift is the low HP and good, wide tires. It will drift quite beautifully though and very controllably, just the limits are so high that most drivers can not even approach them. My good friend had an E46 M3 and with 245 fronts and 275 rears we both had no trouble managing 50+mph slides, so the car's balance and suspension won't work against you. The rear suspension on BMW's is usually pretty stiff from the factory, but BMW dials in understeer by staggering the tires. They even got complaints on the '95 M3's (235/40 at all 4 corners) that the car was too tail happy, so E36 M3 Evo's got 225 fronts, 245 rears, and E46 is 225 front 255 rear. Switch to a non-stagger and the cars are very slide friendly.
In case you don't know, I'm the guy with the black E36 325 who goes to most DG trials events. I've had to run skinny rear tires cause of my sorry power levels, but I hate doing that because while it makes power oversteer easier, it really makes the car a handful for lift-off oversteer and inertia drifts. Ehh, no worries, the turbo goes on soon....
Oh and as Matt mentioned, (Matt, I'm always surprised by your random knowledge of BMW's), you should get a GT oil pan and pickup from BMW. If you can;t do that, at leat make sure you're running 7.5-8 quarts for any kind of racing event.
Cheers,
Sean