From my viewpoint, with a background in racing for 20 plus years, the stock MazdaSpeed spring setup is already pretty optimal. I understand everyone wants to lower their cars, but frankly, I bottom mine now .. with a lowered car you will be either A. driving slow, or B. bottoming out a lot more.
Strickly from a performance standpoint (not looks) I would spend some time valving the shocks with more progressive bump valving to eliminate bottoming, and less rebound in the front to further minimize wheelspin. That kind of stuff probably sounds pretty boring though ..
eibach does track testing on all enthusiast vehicle releases (evo, sti, this car, etc). if it (the pro-kit) doesn't improve overall performance vs. stock, it won't be released. that is one reason the release of this will take some time once things move along.
keep in mind a lowered vehicle effects so many things, including many times an increase in gas mileage, decrease in braking distances, etc etc. the enhanced appearance goes without saying. i feel that the pro-kit i have installed on my ms3 makes the car look absolutely ideal, as does anyone else who has seen it, esp side by side vs. a stock ms3.
if you are bottoming out the suspension now on a regular basis (which is...odd), then a dialed increase in rate with a slight lowering using a progressive spring should not be any
worse. you say "background in racing of 20 years plus". i'd say the average driver of these cars is driving the way you are when you are bottoming out your suspension, <1% of the time out of their entire time in the car, if that. you are not the norm whatsoever. you are a much much more aggressive driver than most and probably ARE in need of an increase in rate AND some sort of aggressive valving change in concert. Mazda had to compromise to cater to the broad cross-section of the niche (there's an oxymoron!) of people who would buy the car by making it lower than a stock 3, with a slight increase in rate and associated valving adjustments to firm up the ride and up the performance, but not make people complain about it being too low and/or too stiff. they figured people who think it's too high, as usual, can lower the car if the choose, but if it's too low out of the box and people are hitting things and feeling like they are in an STi, it, in there eyes, would be one more reason why people would choose another car in this range instead of this one.
