Cars: I heard about the historic Trans-Am cars mentioned and thought I should bring up this site:
http://www.historictransam.com/homepage.htm I know Chad Raynal, I worked with his brother and cousin at an indoor go-kart track in Santa Clara, CA that closed as of February. Chad still races his historic Camaro when the historic Trans-Am series comes out west.
We can name cars left and right until we're blue in the face. I'd like to see more performance oriented cars (and light trucks/SUVs) from: General Motors, Ford, Chrysler, American Motors, and Studebaker. What makes and models? Whatever comes to mind. This includes the muscle cars of the 1960s through the 1970s, into the fuel crunch of the 1980s, and onward to the power numbers that the 1990s and 2000s have seen. The 1980s Ford Mustang 5 liter was a big hit when it came out and it still is; it's one of the most modified cars out there. Up until their demise in 2002, the LS1 powered Camaros and Firebirds were the best bang for your buck. I love many American cars. If you ask me which one(s) to put in, I'll simply answer, "Yes." As in as many as will fit on a Gran Turismo DVD.
Tracks: I'll touch on this lightly as it's not exactly the topic at hand. I'd like to see the past variants of Laguna Seca and Sears Point. I'd also like to see SCCA and NASA club tracks that are in the U.S. but aren't featured in past versions of Gran Turismo. Buttonwillow, Willow Springs, Streets of Willow, Road Atlanta, Lime Rock Park, Thunderhill, Portland Raceway, Phoenix International Raceway, et cetera.
Now on to my own main point. Competition is great for the market because only the strong survive. What happened with BETA versus VHS? VHS marketed themselves better even though BETA was the better product. With some new competition to G.T. (Forza and Enthusia), Gran Turismo better step up to the plate or they will sink (read: there will NOT be a Gran Turismo 6, 7, ...). Forza has included car damage. They've got some licensing of manufacturers that Gran Turismo can only dream of. Forza also allows for motor swaps. Enthusia has some hot cars that Gran Turismo has so far missed out on.
Think about this for a second. What if Gran Turismo had a "parts bin" in your garage? What if you could take the 454 out of the 1970 Chevelle SS and implant it in the 1969 Corvette? What if you could buy an all aluminum crate 427 from Chevrolet and install it into the Camaro SS? How about buying a stroker crank from Ford and stroking a 1970 Mustang's 351 to a 408? What if you could refurbish, sell, or install certain parts from your parts bin into other cars? We all know about porting/polishing and engine balancing from Gran Turismo 4; though in the game they cannot be undone. Maybe that's true, but what if we could P&P and balance certain parts? Then we could put on or take off those parts as we wished.
Basically think of everything we do when we build hybrids (thanks to Mk and others) and imagine these features as coming with the game?
I do think that Forza hit a homerun with engine swaps. Let's hope that Gran Turismo follows suit and raises the bar with its next rendition. Otherwise I know a good amount of people are going to be ditching their Playstations in favor of X-Box and Forza.