If anyone knows of a car that can have AWD and is super good at cornering please let me know, i’ve been looking for this combo in a while, it’s just super fun to drive one of these. 
What class? I like to race at S1 (which happens to be possible on most cars without major swapping), and find anything with a slightly forward balance and about 65% rear differential can pull itself out of a slide with the front tires quite easily… If you have enough power. That’s why I say I like S1, as I can pick a good variety of parts to tweak performance without being too strict on class. The 92 Celica with the rally I4 is a beast, as is the 80’s Quattro with the stock engine upgraded. I’ve even got that ugly little abarth tuned to something like 851-PI and it just does what you want it to.
labo Hurracan HE, in S2 class it’s almost fully upgraded at 998pi, it has fat front tires so it can corner, it has skills boost which is a must for XP maximization, it can hit 269mph.
It is my most used car. I have a tune for it if you need one.
I don’t usually go by class, but i guess an S1 or S2 will do nicely, or even an X if possible, all i want is something with the most lateral G’s that drives with all wheels.
I might try to get that Huracan HE to see what it’s like.
I have a very good Radical tune for Fh3 that slides and corners, depending on entry. I am more that willing to help get tune. It has a 2.01 lat.
I have many S class AWD tunes shared that are circuit or Goliath tuned. The circuit tunes can run on Goliath but not all Goliath tunes will work on circuits. You asked what AWD is super good at cornering and there are so many types of corners in Horizon 3, it is difficult to answer an open question like that. Pure driving fun can be achieved with many super good cornering cars.
Porsche 918 Spyder
Keonigsegg One:1
Ferrari 458 Special
#7 Bentley GT3
Radical RXC
Pagani Huayra BC
Lamborghini Centenario
McLaren P1
Aston Martin Vulcan
Nissan Nismo GT-R Super GT
I can go on and on. Most of the cars on this list are grip monsters and the others are rockets that have excellent handling… I like the Bentley for tight circuits. The 918 for all circuits and the ONE:1 for Goliath.
My porsche 918 spyder is my best cornoring car. I made it to 33 on global in a speed trap (out of 1.1 million people). so it is pretty good. It cost me 14 million at auction though .-.