Stock Car Extreme is awesome. Niels is absolutely fantastic in getting the most out of the ISI engine. Having said that, once you start pushing the car and getting up to the limits, playing with and controlling the limits, etc. it's still 'ol ISI physics with all the usual unnatural, wackyness once out of the physics engine's "sweet spot".
Having said that, 90% of my simracing time for the past 12 or 13 years has been with ISI physics games (especially rFactor 2 and Stock Car Extreme in the past 3 or 4 years) as they are still very fun to play once you adjust and get used to "ISI Physics Land" but, for eg., get the Live For Speed FV8 or F1 and it obliterates ISI physics when it comes to controlling oversteer, how the vehicle behaves during oversteer, how it reacts during oversteer based on your inputs, how the car behaves during the recovery half of oversteer, the way the direction of travel of the car points to relative to the rear rotation, etc. etc. You don't need to get used to "Live For Speed" physics land; I control and correct oversteer just like I do/did in real-life road-cars and racecars. Do this in "ISI Physics Land" and you will either crash, drive sharply laterally across the track (as if you simply decided to turn sharply rather than oversteer), snap overcorrect the other way, or the car will continue rotating as if the vehicle simply doesn't respond to steering inputs.
Once you learn the limits of the physics engine and how to drive and save oversteer according to "ISI Physics Land", then it is really fun but those moments are still frustrating because it is still quite odd, unnatural, and "digital" regardless of whether you save the slide or not (it's not only about saving the slide, but doing it in a natural, intuitive way). Those areas are still all wacked in ISI physics. Also, low speed grip is still weird where cars need to be "pointed" through rotation to get around corners rather than just relying on sheer grip, if you do that then you risk massively understeering as if the track's friction was suddenly lost. Again though, stay in the physics engine's sweet spot and it's fantastic.
The FFB is setup to be very natural and clean. I feel it's quite vague and uninformative/bland at times especially when it comes to front tyre grip and generally braking but it's "clean" and natural because of realfeel and properly setup suspension to go with realfeel.
Until the core engine itself is changed/updated/modified, those wacky areas outside of the core physics engine's sweet spot will never go away no matter how fantastic a job a car creator/modder (Eg. Niels H.) does at adjusting/inputting different variables to drive that core physics engine.