Event Overview
The Yamayama Cup was held on the indoor asphalt track at Rajicon Tengoku Nagoya. The track is flat and offers very high grip. In these conditions the car tended to feel slightly oversteery, so I made setup changes to suit the surface.

1. Ride Height and Droop Settings
To match the flat, high-grip surface, I ran a relatively low ride height.
Baseline ride height: Front 4.2 mm, Rear 4.4 mm
During runs, when the grip started to drop, I adjusted the ride height by raising both front and rear by about +0.2 mm. This simple change improved overall stability around the entire track. When lowering the ride height, I also reduced droop accordingly.
Measured at the outside of the suspension arm, droop was:
Droop: Front 6.0 mm, Rear 4.8 mm

2. Damper Setup Adjustments
The tires used this time were soft, and the track grip was extremely high.
Under these conditions, the car showed noticeable pitching (front-to-rear vertical movement). The front end would dive too much, which led to oversteer.
To solve this, it was important to eliminate the difference in damper behavior between the front and rear. The TRF421 normally uses different damper ends front and rear to intentionally create a difference in movement. This time, I needed to standardize that behavior.
Specifically, I used the damper end "2" from ITEM 51743 (SP.1743 V Parts) - which is originally intended for the rear damper—also on the front damper.
By installing the same damper end front and rear, the damper characteristics became more consistent, and the front end movement was better controlled.
Changing the damper end also raises the spring position. When the spring position is lower, the car reacts faster, so raising it helped to calm the car down.
With these adjustments, the oversteer tendency was greatly improved.

I hope this helps as a reference for setups on similarly high-grip surfaces.