It’s a single spec series, the cars are, theoretically, all equal (although there have been quite credible suggestions that some may be “more equal” than others) so the difference in performance is all in the quality of the team work on setup, they theoretically can’t modify cars and have to use original parts.
Dallara builds the cars, characterized by carbon brakes, paddle shifter and ground effect aerodynamics, Mecachrome builds the engines, 4 liters V8, Bridgestone supplies tyres.
The car is designed for a 3 years cycle, so 2007 is going to be last year, each year it gets some small improvements.
In 2005 they were using grooved tyres identical to F1 (apparently the same used in F1 in 2002 or 2003, I don’t remember), in 2006 they switched to slick tyres and corrected a few issues with cooling that also allowed to increase a bit engine rpm, for 2007 some modifications on aerodynamics are planned, mostly to make it aesthetically more similar to a F1.
Testing is limited to collective sessions, a very small number during the season.
Race weekend is composed by Friday with free practice and qualifying to establish grid for the long race (pole gets 2 points IIRC), the long race Saturday with compulsory pitstop (point system same as F1 + 1 point for fastest lap), and the short race the Sunday morning (6 points to the winner, then 5,4,3,2,1 + 1 point for fastest lap), Sunday grid is formed by result of first race with reversal of first 8 position, the 8th of the long race gets pole.
In term of laptimes, as average in 2006 they were in the order of 10” slower than F1.
The drivers very hardly get paid, actually in most of teams they have to pay for the seat, via sponsors. Maybe some lucky guys with strong support for some sponsors, can find a way to get something on the pocket, but certainly isn’t the norm.
Here a few pics of the car I took this year :
[IMG:150:128]http://img179.imageshack.us/img179/8814/gp201lz4.th.jpg[/img]
[IMG:150:128]http://img214.imageshack.us/img214/3354/gp202qj6.th.jpg[/img]
[IMG:150:128]http://img242.imageshack.us/img242/2428/gp203hn8.th.jpg[/img]
[IMG:150:128]http://img179.imageshack.us/img179/6627/gp204zk6.th.jpg[/img]