I really like the way GP500 plays compared to SBK200/2001. Much more realistic handling, even if the graphics aren't as good.
New tracks are still a dream,but there is work going on and one of the original creators stopped in the other day to check things out and he said he'd take a look into getting a source code for the game or anything that might help in the way of developing new tracks. Talkis cheap though, it's been promised before.
As for the new bikes, YES, they are new MODELS. The old bikes are long gone and everything has been updated from the skins, to the fairings, wheels, brakes, etc. There are slicks, wets, street tires, Bridgestones, Dunlops, Michelins......... Everything has been updated including power and handling characteristics for the new bikes.
If you're just getting started, you have a long, long way to go and you need to be somewhat computer literate to even get started. There are a few.dkz files in the game, that once opened, allow you to get in and insert all the new updates. It can take quite a while to understand what's going on and how to change things, but once you do, it makes the game 100x more enjoyable. Every couple weeks it's like having a new game. I even have a 1998 R1 model painted just like mine with a rider in a blue/black Kushitani Dragon suit and Blue haga Replica Arai helmet......just like mine. My original avatar was a snapshot of the game.
You need to go to the GP500 Store and download the tutorials on how to get started editing the game. If you have any questions, let me know and I can try to walk/talk you through them.
As far as it being played online, I've never tred it, but I think it may be possible. There are worldwide off-line championship leagues that run off of this site http://motogp.2in.de/