Have to honest, I've not really played with setup that much. Leave it on a safe set up and drop the ABS/TC to 4 each once everything is warm. Only thing I tend to do is reduce fuel to make the car a bit quicker. Makes it more unstable though
Ah well tyre pressures make a huge difference so even if that's the only thing you tweak, you'll notice a huge difference. Do a few laps to get the tires warmed up and then adjust the pressure from there. Driving around on under/over inflated tires loses you a tonne of time (I did a league race on Monday night in the Merc Evo at Kyalami and my pressures dropped from mid 27s to low/mid 26s and I was losing 1-2s per lap.
Give the aggressive setup a try too. They're usually really stable and a significant improvement over the safe preset, you maybe just need to bump the TC/ABS up a little.
Also check out the brake pads, 1 is super aggressive for races up to 90mins, 2 will work for 12hrs, 3 is a wet pad and 4 is to simulate worn brakes, although it gives you the best performance but only lasts 15-20mins.
Engine maps differ in every car too -
https://www.assettocorsa.net/forum/index.php?threads/ecu-maps-implementation.54472/
I don't know why any of this info isn't in the game but there you go.
I've not really tried the Huracan too much, I've been toying with the Ferrari 488 GT3 Evo and it seems quick but I can't get the setup right where it's not super squirrely. I'm relying on a ton of rear wing which is great through twisty tracks but not so good on Monza where I'm losing a lot of ground in the straights.
Dedicated server is up and running Spa - search for OCUK in the server browser and the password to join is 'overclockers'
I know what you mean there. It takes some getting used to, especially if you're used to the front engine cars. I've found dropping the rear ride height helps a lot, even to the point where it's lower than the front, and allows you to run lower rear wing.
Also, if you're using setups created pre-1.6 (which in the Evo you won't be unless you're loading 488 non-Evo setups), you need to lower the rear ride height to get some of the rear stability back. It's explained a little in this video -
https://www.youtube.com/watch?v=xdG-9krSQXY