Thank you for explaining that, its very insightful.Completely different handling cars, the 458 has very precise and sensitive steering, feels almost like a single seater racing car, it turns in really sharp but on the limit it will snap quickly into oversteer, again feels like a racecar with this pointy turn in. You can go much deeper into a corner and leave the turn in later in the 458 but you have to be careful with the throttle applications, you can't just turn in and floor it and expect to get away with it in the 458, this is especially true in the wet.
The GTR is much more predictable and easier to drive, the electronics will often get you out of trouble if you don't panic but right on the limit they still move around. The biggest handling issue is quick direction changes, in standard trim the car is a little sluggish turning in and then it rolls due to the weight, if you then have to hustle it the following way it is reluctant to follow the steering angle, this is shown up at places like Becketts at Silverstone and Surtees at Brands, this is where the uprated roll bars help to stiffen it up and stop it leaning over and moving the roll centres around. Anybody who has driven a GTR on track will know it doesn't drive itself but it does make things a lot easier.
I think that is exactly what's happening.I do wonder if it is just the mass of the GT-R at the front which is causing you some concern, coming from a relatively low frontal mass of a mid-engined car into something with a large engine in the front and more sluggish turn-in response, as Barry says?
A GT4, for example, is totally different in corners, especially at initial turn-in. The GT-R is more sluggish and maybe this is undermining your confidence as 1) if you're arriving at the corner at a higher speed than you were used to you may be over-braking to compensate; and 2) the car feels (relatively) unresponsive initially, almost like it is wanting to understeer (or just that waiting-to-bite feeling) compared to the agile Ferrari.
As people have said, CAT DT will probably be your best bet as they will get you to learn the dynamics of the car. After this, play with suspension and ARBs to get the set-up that YOU like.
I could not believe the difference of the springs! They have gone soft springs and hard on the dampers. Instead of earlier years having a higher spring rate. Mine on Eibachs now is perfectEcho the suggestion of CAT DT if you've not done it, very useful.
Also front quaife diff and handling package will help immensely, as will an uprated DSC controller, which will improved all of the suspension settings. Assuming its a EBA model (MY17+) which has softer springs for a more GT'esq/softer feel than previous years.
Out of curiosity just had a look at the Top Gear track times at Dunsfold, standard R35 almost 2secs quicker than a 458 Ferrari ! A modified R35 with a bit more grunt and some suspension improvements would completely destroy a 458.