I disagree that it's quite as formulaic as you think, though. You can certainly find a forumula and stick to it, but trying different things is worthwhile.
I think I didn't express properly what I meant. In the Kee/Old version, some engine combinations where almost impossible to make run. In the UE/Campaign version you can just decide arbitrarily engine capacity and layout and you can always find a compression/timing combination that makes it work.
And finding the optimal solution is easy, because all the governing equations became directly proportional and the number expose a lot of their internals, so a two pass tune will always get you into the optimal spot for performance/efficiency you're looking for.
which is fine, the point I'm trying to make is not that less hard = worse game, what I'm trying to tell is that almost all kind of car you can dream of has a solution and a market, so in the new version there's almost no way of engineering a car wrong, the only risk is being unable to produce it at a decent price point.
that was in answer to the guy which had some trouble in building cars, as in: the business aspect is now quite more important than the engineering aspect, especially compared to the initial engine simulator.
made some pretty good cars [without] fine-tuning sliders until the desirability stops going up
yeah that kind of fine tuning usually makes the car unsuitable for other demographics and makes competitor cars impact much worse if they happen to improve squarely what your demo had asked you to optimize for, I usually refrain myself from doing it even if I'm leaving 20 points on the ground it's almost never worth it in the long run (exceptions: supercars and luxury, because these dems are monodimensional anyway).