A bit of a torture test / shakedown & the Z4's first track day this year.

Since last year...
- Major cooling overhaul (2x auxiliary radiators, water-to-oil heat exchanger)
- 200TW tires at last (RE-71RS, used, 255/35R19 square setup)
- M3 monoball front suspension arms
- Limited slip rear differential

First Z4 track day with the MHD Stage 2+ tune (the most aggressive & heat-generating tune I've run).

~~ Dropped my PB by ~3 seconds! ~~
0.5s slower than my PB with the 997 and its original motor. :)

Downside was overheating within ~5 laps (~7 minutes) driving at full tilt in 80°F weather; needed to balance cooldown and hot laps to get far into a session.

For posterity, the peak temps I recorded included oil at 272F, coolant at 244F, IATs at 180F, and a misfire which developed at the end of the day (perhaps from coil pack overheating). Ironically, any one of these overheating issues would have resulted in a strong desire to improve that system, but as-is I think the car is well-balanced. It's not meant to be a dedicated track car (really more of a backup track car, primary AutoX car, and year-round daily), so in general I'd say it's far exceeding my expectations.