Yeah, I've seen it. At BotCon 09 Paramount Party I got to talk to the fella who drove it onto the lot. He said because of all the mods it handled horribly and had a turning radius of like two degrees, but it was still a thrill to drive. I was all jelly.
That's a really hard choice. I really like pretty much all of them, but my favorites are Sideswipe, Soundwave, all three Wreckers (weaponized), and Megatron.
If I had to pick only one from all 3 movies, it would definitely be Barricade's Saleen. That thing looks so freaking cool and "to punish and enslave" is a great addition.
More of Mercedes person. but Bugatti Veyron all the way. Love this car! Cost: Over 2 million, base price Satus: Fastest road legal car in the world. 408.47 km/h (253.81 mph) Random Fact: A replacement transmission for the Veyron costs just over $120,000. (US)
By far the Wreckers. I love their armored weaponized nascar look. My favorite after those would be Megatron.