Not quite sure what you're getting at here Westy, but I'll readily admit to having a bad day, so perhaps it's me! I'll try this to see if it's anywhere close to what you want:
The drivers know how their cars work, and understand how its features [components?] should interact with what is already known - and thus; how performance should be affected - very thoroughly indeed. This is central to the driving job. However, as is always the case, some can do it better than others.
The driver's role is absolutely vital.
- There's nothing quite like actually verifying predictions and then providing the all-important feedback in order to make more accurate assessments, with ever finer tuning. This is what testing is all about. If and when predicted improvements fall short of reality, a re-think may be needed, or sometimes the idea is shelved altogether! Modern-day simulators are very very well programmed with bucket-loads of data, but even the simulator needs a professional driver in order to test (verify) outputs against expectations.
To put it another way - and in the most fundamental sense - an engineer primarily designs things in order to accommodate the driver, which is inevitably based upon the driver's personal preferences. If a driver finds a benefit (or not), it is something an engineer will factor into any recommendations for adjustments; or indeed, to future designs. In this sense, it can be seen that it is very much a team effort between driver and engineer, who lean very heavily upon each other to find improvements.
