Don't forget the newly GT5 Sponsored Peugoet 908 LM Race Car.
And yeah, GT is the reason why the Lancer and the Sklyine have made it to US shores. I also made people aware of the Impreza/Lancer battle and introduced the world to some VERY unique cars and brought to life manufacturers that probably would never have made it other wise...or at least not have been nearly as popular. I mean: Vector, TVR, Spyker, Pagani, and Proto Motors all, save Vector, made their video game debut in a GT game and now their a lot more widely known if they haven't appeared in a GT game. It would appear that GT5 is going to give some more baby car makers a new life, as well.
Also, I believe GT4's manual had a intro from Skip Barbur of Skip Barbur Racing School which uses GT in their teachings. Also, Tanner Foust has mentioned several times that he loves the game. And Jay Leno's Blastaline Special appeared in GT4 after the PD team visited his garage to gather sounds and info on some of the cars. Mr. Leno went on to do voice work for GTPSP.
Also keep in mind that NASCAR came to KAZ and ASKED to be included in GT5. They even went so far as to invite Kaz to a race. NASCAR drivers like Tony Stewart and Earnhardt Jr. are BIG fans of the franchise and when Nascar dropped their license with EA, they pratically begged NASCAR to consider PD to build the next NASCAR game.
Soooo...yeah, a bit of a MASSIVE influence on the car and racing industry....also...did someone mention that a lot of car makers are going to be using GT5 as a testing ground for concept cars. It was mentioned a while back when GTHD was going to be GT5 that one could pop into an online race and there would be a strange car in the lineup that you couldn't yet play yourself. This car would be driven by one of the developers of the car and would judge people's reactions to it and from those reactions, would deside whether the car is released or not.