Well, yes it is, but they'll never add it. it's just not the type of racing Gran Turismo incorporates. Though very few of the races in GT7 represent anything close to most real life professional motorsports events.
None of the vehicles in GT7 will be licensed to be represented in illegal street racing. There are aome manufacturers like VW who flat out will refuse to let their cars be used in such a capacity. Though most dont mind for the right fee and terms.