It all depends. However once you have the setup correct in its basics, then most of the speed on track is down to driving skill. Indeed, if you're 6 seconds off the WR, then the WR setup isn't going to help a lot. Setups are very overrated when it comes to whether you're competitive on a public server or not.
Well just for the sake of discussion (as gentlefoot is obviously bored )
A quick test with AI in UF1's (least setup options) arround AS Cadet Rev (short track) shows that there is a little less than 2s between the AI using the default hard track set and the AI using a set closely approximating the WR set. The fastest AI was nearly 3s off WR pace and the slowest AI using the Hardtrack set was 4.5s off WR pace.
So a quick conclusion we can draw from that is that if you are 6.6% away from WR pace then a good set might net you a gain of 2.6% closer to WR pace while improving driving skill will give you a net improvemnet of 4% closer to WR pace.
From this we can see that improving driving skill will give the greatest improvement, but we can also see that setup does play an important roll. Say 40% is down to setup and 60% is down to driving skill.
There are some factors that aren't so obvious that can change this picture dramatically though. Factors that affect you driving confidence which I belive actually tip the balance more towards 50% setup and 50% skill.
An experienced driver can take a poor set and get reasonable results out of it because they "know what they can do" and therefore have confidence that they can achieve the best the set is capable of. An inexperienced driver on the other hand is all at sea when the car behaves not as expected which sets back his confidence in the car/track combo, causing him to drive more timidly as he becomes unsure of what is possible.
So a better set to a novice driver (that is keen to learn) will increase the speed at which his driving skill improves by giving him more confidence in the car/track combo.
My personal opinion is that sets and driving skill is optimised when they develop side by side, you shouldn't really seperate the two.
So advice to a novice driver that is 6% or more away from WR pace would be to get a decent set they like then practise at improving their driving skill till they are within 2-3% of WR pace.
From that point onwards set development and skill development are much more closely related.
I guess it depends how bad the setup is that they're currently using. If they're 6 secs off the pace using a setup that handles like a drunken elephant and has the downforce set at completely the wrong end of the scale then a great setup would probably make a big difference. If they're 6 secs off using a setup that's reasonably drivable, then yes, the setup isn't the problem.
Try this experiment....... Use "Race_S" set, if you get within a couple of seconds of the WR switch to the WR set.
As we have seen in team racing on the DMR server the past few weekends. Everyone uses the Race_S set and most people are around the same times. But there is always someone (Alien) who can make that crappy feeling set go a few seconds a lap faster than everyone else.
So I think it isn't the set that makes me slow, it is my abilities or lack there of.
Another thing ive learnt as a Demo racer in Blackwood is that in an XFG me using my edited setup my car goes about 3 seconds faster when i take the corners at a comfortable pace rather than when i push the car to the absoulute boundary.
right now my fastest is 1:35:XX and that was wen i did a nice comfortable lap. However when i push the car i get 1:39:XX around which goes to my theory how mentality can play a role, if u are patient u will get results though when u try to push ur car u tend to make mistakes and wear your tires out like crap.
)