Well of course TOP would make them... if they didnt want to continue to develop the product then they would still just have the foam spring set and nothing else.
Its obvious TOP is still interested in development of the car, every few weeks or so we have updates of new parts becoming available. One of the newest parts was the shorter steel bones. Why were these bones produced? Well, through the end user TOP realized that the longer bones created problems (broken blades) and the shorter aluminum bones wouldnt stand up to the abuse of a spool in the front end.
Its all part of development.
So when someone says, 'Hey guys, i found that you can use the softer springs from other manufacturers and they work pretty well', and someone else pipes up and says, 'Those are unneccessary, what comes with the car is just fine', then i feel that person isnt part of the developmental process. The rest are just nut swingers...
Trust me, softer springs work fine on the car... and looking for 'mechanical grip' elsewhere doesnt mean it will be the fastest the car can be. Roll center has to work in conjunction with spring rate to control weight transfer of the car at a specific static weight... on a given grip level. 306's are NOT the answer for every track.
As a matter of fact, i would love for some of these convinced racers to come to our home track, and try to run their current setup that 'works just fine' on our less than grippy surface. Ill bring the cam to post up the aftermath. Bring spares...