wow. Just plain …wow. I realize tire tech has improved over the last few years …cars in real life are runnin 9’s in the quarter with 10" slicks these days as opposed to needin at least 12" and more was better.
I use a joystick-throttle for input.
First bit of tuning was steering linearity, I set it all the way left to zero so I have very fine control at center, takes all the twitch out …can thread thru cars at speed fairly well.
Second was setting deadzones both in and outer so there aren’t any …I get full input from lock to lock, no ambiguity.
Your mileage may vary.
Played GPL back in the day, for years. Ran into some here n there who actually raced …Indianapolis, NASCAR
…and myself …well I was into doorslammers in the NHRA for nearly 20yrs.
And street racin. Oh yaa … before everyone started bringin guns an such.
Built and raced some great project cars over the years.
Anyway …Forza captured me when 3 came out …one of my biggest gripes was controller input …it just does not offer the fine control required 
F7 …well … I was jazzed the moment I found out it can run on a PC.
Impressions so far?
umm … I don’t sleep much, food schedule is out the window, dogs think I left even tho I am sittin right here
…and the wife says she likes not fightin for the covers lately, since I am not in bed.
Like F3 long ago… I began with the Datsun 510… built it to run in D400 class and easin into the game usin it in Freeplay …LeMans mostly.
Turned off most of the assists (still use auto-shift and brake ABS tho)
…with the 510 you have to be careful addin any tire up front …it will swap ends on braking into a corner very easily if you add anything to the front.
Need the roll cage so the car us stable apexing a corner and a few bits to cut shift times (clutch, tranny) and sport compound tired, along with light wheels.
Settin race limit to D400 class… the lil Datsun annihilates the class. Can hang in the crowd and not push into bad situations and just let it rocket the straights.
Another bit I noticed …when you go into tune dialogue, first screen with all the options (tune, upgrade an such) …lower right is Forza Preset body kit option…
…for the '68 Hemi Dart this option alone gets you the blower and 1075hp … similar for the '69 Camaro … that just made my day 
Stiffened up the rear, softened up the front, dropped rear tire pressure to 15lbs, rear gear ratio tweaked so she is at top of 4th gear across 1/4 mile finish line
…and voila . . the lil Dart pulls the front wheels on launch, not for long or very far …but … it launches like a Hemi car 
I will be at this awhile … I am soo sucked in 
-Frank