Road Racing - ESP Class ?

Just wondering how much time difference should there be between say.....SS class vs ESP class.

I ask because locally keep seeing an ESP 01 mustang cobra running within 1 second if not less sometimes from an SS 04 Z06.

Both on A6 315 hoosiers, BTW.

I went for a ride in the Z06 and the guy is a good driver. I guess what I'm asking, does that sound right?

I just looked at the recent solo series results and I guess thats about correct.