heres some generic setup tips.

~PP~

performance points are the equalizing factor in GT. i like a balance of settings in here b/c this section is prob the least relevant. except for the daytona oval in which you can give it a little more power then usual and not get placed at a disadvantage.

~suspension~

-ride height
you want the ride height to be close to the bottom on the fronts and slightly higher in the back.
-springs and dampers
springs are either soft (low #) or stiff (high #). these setting mean the car can shift its weight around easily or make it harder for the car to shift it weight (soft or stiff).springs should be soft (low numbers) for the most part (should be a bit stiffer for londons "curb jumping" type race). dampers are connected to the springs in that they define how easy it is more the springs to compress. low damper numbers mean the suspension can more easily compress and rebound. higher damper numbers mean it will make it harder for the springs to compress and rebound.

this subject could go on forever but ill try to do it briefly. heres and example or what suspension can do.

if the car is oversteering coming out the of the turns 1)ease on the gas2)put the front springs at like 4-5-6 and dampers the same, and put the rears at like 2-3 and the same with the dampers. this will allow the rear of the car to come down during acceleration and give the tires much needed grip. the front settings are stiffer to help the front come up during acceleration which also helps get the rear down. this is just one example of infinite possiblilties with each individual car (FF, R, AWD). i hope this example gives some hints as to how suspension settings help in an actual racing scenario.

-toe

toe is more interesting then alot of people know. unless your on the daytona oval these settings usually help.
the front toe setting should be in the negative range (toe out). i usually set it around -.23. toe out on the front helps with "turn in" meaning the initial turn movement into the turn. the reas should be in the positive range (toe in). not such high settings on this. i like mine around +.10. this helps with grip coming out of turns under acceleration.

-camber

alot of you know what camber does already. negative camber leans the bottom of the tire out away from the car and helps with grip when the car leans into turns. too much camber will hinder you b/c you have so much angle on the tire that
your turning and you not getting the optimum amount of tire patch on the surface for grip. in general settings should be 2.0-3.0 on the fronts and 1.2-2.2 on the back.

-brake balance

can usual be left as is. maybe give the backs a 6 instead of 5. but not much else for these cars on these tracks.

-turn, TC, ABS

turn can be left at 40. traction control can be used if you are constantly spinning out under acceleration. around 4-5 helps with any problems and doesnt hinder your acceleration much. ABS is how much braking stability you will have on turn
in braking and also during turns themselves. generally a 3-4 will give enough stability on hard braking and "turn in".

~gears~

gears are relatively simple. just takes a couple practice laps to figure out. 6th gear should be set for the longest straight meaning 6th gear almost gets to redline when you get to the end of the longest straight on the track. the rest of
the gears should be spaced accordingly. do a couple laps and make sure that you are not having odd moments b/c your
having to switch gears mid turn or right before braking.

i hope this generic guide helps. if anyone has questions, just send me a pm. ill do my best to help :) good luck and good racin'