Kmas and Adam i think both of you guys should pick one up, this is my first f1 car and have been enjoying it a lot...
in terms of rubber tires, get the tamiya type B or soft rears and option front ... fronts are hard... tamiya also has rubber tire wheels... remember the black ones that the kit comes with only work with foams..
the other two popular brands are ride tires and pit shimizu's, i have not tried either but I know that for ride tires you need to get the ride wheels they dont work with tamiya wheels... i will be trying the pit's because from what i am reading they perform better on the f104...
i have also used the type B front and rear foam tires, which are at least .5 to a 1 second faster than the rubber tires..
most people seem to run the cars with the stock silver can because of tcs or will run 21.5.... i have been experimenting with 17.5 and have been recording slightly faster laptimes compared to a 17.5 boosted touring car