This is just my personal opinion, but that particular car doesn't get my blood flowing. While the price is excellent for the mileage, the SMG and color combo doesn't really cut it for me (plus you already have a Jerez Black).
The E46 is already a basketcase in terms of maintenance, so an MT would have to be an absolute must. Secondly, I'd go for a crazy color like Imola Red or LSB, although I realize that's not for everyone.
Personally, I'm deciding to skip the E46 M3 (had a regular one) due to reliability of S54.
Current: 2008 BMW M3 Sparkling Graphite/Bamboo Beige/6MT. 1999 BMW M3 Techno Violet/Dove/5MT. On the list: BMW M2 Long Beach Blue/Black/6MT