F1 is picking up in So Cal? It's been up for a while now.
Go to uf1series.com and see what you've been missing.
The only upgrades you NEED would be a center shock TRF or can go 3racing cheaper but "cheaper"
, front wheel bearings, better spur and pinion gear selection (for your 21.5 get the 93/104 tooth spur set, use the 93t and a 34 tooth pinion, yeh you can mix Tamiya's pitch gears and 64 pitch gears just fine) and Pit Shimizu tires #571 and 572 rubber which will mount on Tamiya rims made for foam tires. Yep rims for foam tires. Been covered here extensively, there's even an entire thread for Pit Shimizu tires for this car. Can't be beat.
Build it to the kit specs, ride height etc but run the damper plates very loose, center T plate/bar screw very loose, light 15 or 20 wt oil and the softest shock spring you can find, gold or flourescent red or even the new black spring for the F104X1. Just keep the rear setup soft and loose.
Of course there are a million hop ups you may "want" but to get your car working, you won't need much to get going.
Get all of your stuff from speedtechrc.com or tqrcracing.com. Between them you will find everything you need.
The F60 kit has the fiberglass chassis and steel rear axle which are both a plus for running on asphalt.
Be sure you go and run it and get tips at Tamiya Raceway on Saturdays, it's free and only open to Tamiya cars/owners.
Glad to help if you'd like to pm me any questions.
This is the car I've been racing for a couple years since they came out, with upgrades of course.