When I was looking for a new watch last year I originally wanted a "driving" watch, but apart from the Monaco, which was out of budget for me, they all looked a bit too fussy. So I ended up with a pilot watch.
Many vintage Heuers - especially the Carrera, Autavia & Monaco just ooze motosport history, then you have the very cools 80's Porsche Design Chronographs & of course the Rolex Daytona was named after the race.
Someone usually suggests the Omega Chronostop, but I have one and wouldn't agree. I have a Heuer stopwatch for when I need to know, although my car has a timer incorporated into the clock, if I could reach it.
My Sinn 303 on a Rallye strap with stitching coloured to match the chrono hands. (Excuse the crap photographs)
The numbers in red on the tachymeter scale relate to the speed ratings for car tyres. On the back of the case is the speed in km/h and tyre speed rating letter.