1024 is def tough to crack but people have done it. Can't post a link but some folks depleted the CPU of power carefully enough to just induce a few errors and after a while they were able to piece together the key.
By the time some of the new F cars are out of warranty I'm sure we will be able to brute force 1024 bit encryption. In the meantime let's focus on the E90 N55 flash tuning and piggybacks. Click here to enlarge
Didn't know it at the time but now I'm glad I got a 2011 335i!