Some S2000 owners, including myself, have gone to a setup where the front tyres are the same as the rears called the non staggered setup. This may seem a step towards increasing the high potential for snap oversteer as many S2000 owners have experienced yet based on my experience, it has delivered so much in gains that I would not look back to regular staggered setup, where front tyres are narrower than the rears, until I can find evidence that the staggered setup performs better.
Let's look at the S2000 setup in stock form. With 215/45/17 tyres up front and 245/40/17 tyres out in the rear, the feel I get is that the intial turn-in is lacking in grip. The result of this is that the driver tends to add more lock to get the car to turn and when the car finally responds, there is excessive steering lock and the tail of the car snaps around. This tendency remains even when camber angles are increased to give more grip to the fronts and it is my thought that this is wholly due to front tyres that are too skinny.
When I shifted to a non staggered tyre setup with front tyres as wide as the rear, the turn in was excellent. Feedback did seem a little numb but you would pretty much know how much grip there was as the steering was still communicative. At higher speeds, due to the high amount of rear lift the S2000 generates along with the fact that I had fitted a large front splitter, the front gripped far more than the back and resulted in a rather white knuckled ride. This left me with doubts about how the non staggered setup had upset the natural balance of the car.
I subsequently fitted a high mount GT wing to balance the tail of the car and the result was phenomenal. Not only did the rear lift get cancelled out, I also retained the excellent turn-in characteristics of the car. This was far more pronounced when I got to the track. When turning in, the car would simply grip and go and I had no need to add any excessive lock but was rather using far less steering lock than before which is easily seen as much more efficient. In the slower corners, I was able to turn in sharply and get the car to rotate (as the rear wing grip was far less due to lower speeds) while at higher speeds, the slight oversteer would change to slight understeer as the balance of grip shifted to the rear. Braking was also a much more stable affair with the increased stance of the car.
I was hampered by a leaking brake master pump, torn in half shifter bush, leaking clutch pump, overly understeering alignment & wrong tyre pressures at the latest track day I attended. This resulted in only a very slight improvement in my personal best laptimes which was a definite disappointment. However, I am confident that after the repairs, the car will be able to hit the benchmark times I have aided by the transformed characteristics of the car.
Even though it seems counter intuitive to conventional wisdom (you can't imagine how many "old birds" of the tracking scene scoffed my new setup) seeing how many performance cars have rear tyres much wider than the front, deeper analysis into racing cars seems to favour the non staggered setup. Many racing cars have front track & tyres as wide or wider than the front to aid their turn-in and front grip with the rear aero dynamics compensating for rear grip. Although its hard to tell on paper which is better, having experienced the difference on the road and track, I am definitely of the opinion that non staggered is the way to go for track-biased cars. The only caveat would be that the driver needs to be experienced enough to measure his steering inputs accordingly.
Considerations on non staggered fitment are the following:
1. Rolling and pulling of the fenders are mostly necessary (there seems no point in my opinion to run tucked in offsets just for fender clearance when the increased track of lower offset will deliver great gains)
2. Camber requires to be to tuned to your driving style (it seems necessary to have a proper data to support better alignment to optimize the alignment)
3. Improved aero i.e. GT wing is necessary (you will be resetting the balance of the car and an adjustable efficient wing will go a long way to ensuring your setup is effective)
4. Some rubbing of fender liners and suspension cars will be experienced (this is an eventuality non staggered owners will have to accept)
5. Fender tab relocation and bumper trimming is necessary(again this is necessary to prevent rubbing of your tyres)
The ultimate caveat here for fitment of a non staggered setup is that owners who want the aesthetic appeal of the car maintained may be disappointed. To clear non staggered setups, the car may be raised slightly, may need body work, may have slightly wavy paint due to rolling & cutting, may have protuding tyres etc. Everyone chooses how they want their car to be and I think its important that owners know the impact of non staggered in the aesthetic sense before they embark on this journey. The track-crazy S2000 drivers wouldn't be too bothered by these sacrifices as the on-track performance would likely be sufficient to compensate.
I welcome any non staggered owners to discuss their setups openly or in private and hope my anecdotal thoughts are of use to any readers out there :)