The Getrag 245 is the common conversion, but known good 245s are becoming really hard to find and preciously expensive. Also, several of the key 245 parts are NLA, so if your trans wears out one of those parts (and these transmissions are generally 40+ years old), you're in dire straits. Conkitchen has a 245 for sale here on the forum.
The Getrag 240 is another option. These are usually a bit less expensive, but also quite scarce. Most 240s lack the speedometer output, so you'd need to rig up a GPS speedo (readily available online) or install a Hall effect sensor on the trans and get fancy. Alternatively, the 240 that came from the factory in 1983 E21s has a speedo output. If you could find one of them, you'd be in good shape.
The Getrag 265 can be installed in a 2002, but it will require serious modifications to the transmission tunnel and firewall due to the larger size of the 265 bellhousing. A 265 is a bit of overkill for a 2002 unless you're putting down some serious HP and/or hotswapping it at the track as might be done in an endurance racer.
Good luck!