I'm running a Neon SRT-4 at Viper Days. I'm using the magnetic mount on the roof. However, you probably can put the GPS antenna (looks like an XM antenna) anywhere it's got a shot at the sky.
When I say "nearly the same", I mean within a couple hundredths of a second. The first time you use the Traqmate at a given track, you need to set "Start-Finish" for that track. That's done by pressing a button on the Traqmate. I usually set Start=Finish when I cross the finish line. Since it wouldn't be advisable for me to stop right on the finish line and set the Traqmate, I just press it during a lap when it looks like I'm crossing the line. Once Start-Finish is set for a track, you never have to reset it; the GPS knows every time you cross that location. Since it's unlikely that the spot Viper Days sets their transmitter is exactly where I press Start-Finish, there can be some variance. The device updates 20 times a second (and you can set it for even more frequent updates), so that's certainly accurate enough for me.