Alright - on Saturday I tried running the same tires from High Plains Raceway. Ended up lowering the front of the car a bit, played with the knobs, and swapped the front tires to the rear.
I ended up in second place in TT5 by .1 second with a 1:49:049, but each change I made session to session had me doing similar lap times, which is a pretty big deal when ambient temp fluctuates from 70f from the first session to >100f by the third session.
Last night I went over the AIM data and decided I was being a pansy so I bolted on a new set of RC1s this morning and decided to send it lap one session one. The balance of the car was basically complete transformed with a set of tires that hadn't been heat cycled to death, go figure.
The car pretty much felt perfect and I cannot convey clearly enough how well the Xidas soak up curbs even when you're being an idiot in terms of curb aggression and the damping set fairly stiff.
AIM predictive timing wasn't working since it was the first lap of the day, but a 1:46:42 popped up on the timer so I headed right in to claim it. The previous TT5 lap record was a 1:48:340, my AMB official time was a 1:46:361. Took the TT5 win today also.
I see improvements to be made in the lap, but overall I'm incredibly happy with how it worked out - I was expecting a low 1:47.
For what it is worth, I never ran the car sorted with the supercharged FA20 but the pretty trash laps I did here while the car was making ~350whp were in the 1:45s. 1:45 was also as quick as I went in my TT4 Miata. 1:48 was as quick as I ever managed in my S2000 and I was incredibly comfortable in that car.
I take this all as a pretty positive sign as far as beginning to be more comfortable with the car. Next two events are at Attessa in a few weeks, we shall see how it goes. KINDA tempted to try a set of Toyo RRs.
edit: Also, jesus, I really need to get a GoPro since this AIM video quality is dumpster tier.