Agree with thstone, day 1 that instructor couldn't help you go faster without breaking out the wallet, but on day 2 that instructor had new things to help you.
At my home track I was sure that the car was holding me back, i was passing every other Boxster, caymans, 911s etc. A pro coach drove my car that day and was 5!!!! seconds faster (on a 2 mile course). Since then (Feb 2017) i have chiseled away 3 of those seconds, and still working on the rest. Have tweaked my setup, but no major changes. But I'm now doing things with the car, weight transfer, rotation, etc things i had only read about and thought i was already doing but was not. I can't to see what my next learning will be
I would recommend GT3 front control arms (well that is a wallet buster
) and around 15-20mm of shims, at stock height that will get you to around -2.5 camber in the front, max your back neg camber at around -1.9, your front will grip better, better tire wear, and with 0 toe in front and .08 degree of toe in per side in back, you won't have excessive inner tire wear even with that camber. If you are not already, go to a 225/45/17 in front vs the stock 205/50/17.
Then drive the wheels off like you have been doing and have fun!!!