Only person Ive had a run with recently was a Boxter on the way back from the Ring, made it as far as Guildford before some bloke was trying to show off and undertook my mate... funny look on his face when I was sat right behind him 20seconds later
Appart from that Ive really stopped bothering on the roads, seems if you overtake or beat someone they only come up behind you at the next set of lights! Either that or your risking your licence. I know what my car will and wont do so dont have to prove it! I find baiting people is more fun, give it a little rev at the lights maybe and watch them wheel spin off up the road, thinking they've rinsed you... then I just smile and carry on my journey knowing I saved myself £5 worth of fuel!