the 2001 are mostly widescreen models. The widescreen is better just cause it's bigger and it's easier to use. Not to mention it looks cooler. It'll also take a TV tuner, dvd player and even reverse cameras without TOO much modification. Both are factory, neither became standard, but if one did it'd be the smaller one. Check www.e38.org
you'll find the answer there in the year to year model changes and differences FAQ.