Coming from S chassis cars where everyone beats suspension upgrades down your throat, are FC factory suspension arms good enough for racing?(let's says time attack for S&G) doesn't seem to be much of anything out there that's not for drifting.

 

For time attack the main supplier for FC suspension parts is Super Now!

The suspension arms are pretty rigid on the FC.
"Just" add sperical bearings to replace front trailing arm compliance bushing and then run adjustable toe arms instead of the fixed stock lateral arms.

https://www.rhdjapan.com/search/engi.../handling/?p=1

You will probably want to upgrade the front hub/spindle as you will get tired of replacing front bearings and the pad knock back.

Super Motobei FC
https://minkara.carview.co.jp/userid/736015/blog/

https://www.youtube.com/user/motobei7fc3s/videos

https://thenaritadogfight.com/2016/03/25/close-up-%E3%82%AA%E3%83%BC%E3%83%88%E3%82%BD%E3%83%8B%E3%8 3%83%E3%82%AFfc35-the-circuit-
samurai/

Super Now owner Imaizumi

https://www.youtube.com/user/superima2002/videos

http://www.speedhunters.com/2008/08/car_feature_gt_gt_super_now_fc3s/