The linked article in this major thread explains why this doesn't make much difference:
http://trafficwaves.org/trafexp.html
In my experience cars are just as likely to cut in as out, and that's what the extra space is for anyway.
If you arrive any later it will be minute or two per hour, so worrying about people "getting ahead" of you accomplishes nothing. If you want to win the race against the others on the freeway tomorrow, leave 5 minutes earlier!
