OP, i thought of you this weekend.
I saw a Z/28 get a 1:25 on a track where i could only manage a 1:33ish. My first time on that track and he is a pro driver (last drove the Park Place Porsche in 2013 at Rolex 24). we are, however, both dentists so that's another variable we can account for. so he's kind of my newfound hero ... dentist / pro racer. I've done a total of 16 track days over the last 6 years but i used 3 different cars and spread those days out over 9 tracks, so i am far from "honing" myself or my car but i'm an "okay" driver. He's been racing as long as i've been alive
me in m3, him in z/28 not fair but he could probably beat me using a stock hyundai elantra. his feedback of the z/28 was "it's a big car but a lot of fun .. not nearly as nimble and agile as your car though" talking about my f80 M3. i think that pretty much sums it up. He said that the cooling seems to be an issue but i forget how he elaborated on that.... i believe something about there being poor air flow (despite the "flowtie" hehe)
a better comparison: this guy in the instructor group who he passed (i don't know anything about the other driver) ... GT3 driver i'm guessing is at least very experienced but may not be a "racer" or a "fast" guy... anyway here ya go:
^^notice the mid-turn brake... he was doing that a lot of laps even when he wasn't rear-ending a porsche though ... i think to get some rotation in the off-camber/flat turn.
^^ same lap couple turns later and he started pulling away .. next lap he was a good 3-4 seconds ahead of the GT3. impressive work.