honestly man, i wouldn't start out with the "best" street autocross tires.. sticky tires really hide bad driving habits. i started last season with some cheap summer tires and i firmly believe they helped me as a driver ten fold.
if you want sticky tires in that size then the ecsta XS tires will be fine. that's what i run and they are grippy enough for a second year driver like myself. especially when i'm still trying to find the car so to speak.
edit: the 205s won't be THAT bad, you definitely want to get the biggest contact patch without pinching but, that's more important at the national level..