If anyone wants to practice before the COTA race I found rentals here:
http://www.motorsports-sw.com/site/
They also can rent a Wolf race car and do race support at CoTA if you don't want to trailer your car to Texas - track time is always limited for COTA so it may be worth renting beforehand to get used to the track before the race weekend starts, and they will rent for track days that are could be too short to be worth taking your own trailer down for. They also can rent a Wolf race car and do race support at CoTA.