FL5 on 245/40/18

[HKSpeed]

Saw this at a car meet. I wonder what is the story. Why go from 265/35/19 Michelin Pilots to 245/40/18 Delinte DS2?

I guess it is fine to save money, like using 87 octane and driving mildly.

The blue Si in the background had 255/40/18 Bridgestones (200 treadwear) on CE28N

Also at the meet: 265/35/18 Lexanis (500 treadwear) on TE37L. When you got no more money left after mods . My guess is these wheels came from another lesser car.
If I had a R33 like this, it would strictly be a garage queen/Sunday cruiser. I would get the same tires

 

[Cueyo]

I'll bet the smaller tires on the FL5 are because smaller tires are lighter and the extra sidewall is nicer on the road in terms of feel. A lot of FL5s are tracked and driven hard, but you don't need all that tire on a daily drive.

Going from my meaty winter tires back to the pilot sports 4S's makes me miss more sidewall