I made a quick very unoptimized run of the F-Zero X Death Race. It is totally unoptimized and I like watching TAS's more than creating them so I decided to throw it out and watch it get completely smashed.
The in-game time for my run is 19.923 seconds. I have no clue what the world record time is, though some claim 23 seconds. The best video I've seen is 55.403 seconds. Seen here:
http://speeddemosarchive.com/yabb/YaBB.pl?board=consoles_newer;action=display;num=1127928791
There are some very obvious problems with the run. Such as the last car being way out in front.
Some tips.
Boost lasts exactly 100 frames.
You can aim when you hit enemies to hit other enemies in front. This does cause some problems though, such as the last car I killed. it gave him a boost so he was far ahead. Which brings me to the last tip I have.
Getting hit from behind gives you a slight speed boost, as cars are destroyed they spin around. If you time it right you can get them to spin into the back of your vehicle giving you a speed boost.
M64 file here:
http://s11.yousendit.com/d.aspx?id=3H46DTWW2I7R90NY0A985XI0RR