I don't have a solution for the connection issue, but I did a search and someone on the official forums said opening ports 43210 and 43211 might help, but no promises. I've never had the issue myself, but it seems to be common on the Xbone; when you say wide open does that mean you have DMZ enabled?
For the summit events, it will show the description on the screen when you select the race. Currently, there are some events that restrict your selection to Italian cars, so it just says "Italy" in the description. If you don't own one, it will provide you something. Other events are completely locked to a specific car and those will say something like "Provided Vehicle" instead.
The parts situation is handled a bit oddly. When you send a part to your HQ, it will be there for only that spec on that specific car. If you were to buy a different car and put it into the same spec, the parts won't be in the HQ, but you may purchase those discovered parts for that specific spec from the tuner. It can get expensive to max out new cars if you buy your parts this way to avoid grinding each car.
The levels of the tuners' starting kits correspond with the levels of the parts they start you with. A level 10 kit will provide bronze level 10 parts for everything in your car, level 20 will provide bronze level 20 parts, and so on. If you plan to purchase previously unlocked parts in the tuner for your new car, buy the cheapest starter kit since you'll just be replacing the parts anyway.
Hope this helps.
Thanks for that, I think that makes sense.
So, for the parts you win, they are only for that car in that particular class, however, the parts you win allow them to be purchased in the tuner for other cars and classes?