Did you know that there are actually two Koni Yellow models? Most Yellows are the 8041 Sport model, but racers often want a shock that can handle even higher spring rates and lower drops, which is where the 8041 Race shock comes in.
While the Sports are said to max out around at 400-600 lbs/in spring rates, depending on who you talk to, their Race shocks have the popular SPSS3 valving and can do up to 1000 lbs/in.
The Race shocks also have a shorter body so that you have more usable shock travel and less risk of bottoming it out, which is a very real concern when you have a lowered car. Bottoming them out will damage them internally, and common symptoms are the adjuster being stuck and/or having reduced range. This happened to both of my old Sports on the rear, despite running extended top hats, good bump stops, and fairly high rates (650 lbs/in). To be fair, it happened on a course where I was riding some pretty intense curbing, plus had a hard off over said curbing.
Are higher spring rates and better shocks worth it for Front 4? Probably not. I do like the Race shocks to avoid bottoming them out as we smash curbs in Time Attack events, but for road course stuff we have not found it to be much or any faster than cars on softer springs and off-the-shelf Koni Yellow Sports. Front 4’s limitations on both tires and suspension bushings are likely the reason for that, so ultimately it keeps everyone more competitive and with lower costs. This is a situation where we deliberately do things differently from Honda Challenge and other classes that allow metal or spherical bushings and much softer/stickier tires… That stuff increases costs and opens the door to other things that also increase costs. We’ve proven to be plenty fast, and very competitive with each other, without opening that Pandora’s Box.
Here are some side-by-side pictures of the Sport and Race shocks for a 3rd gen (DC) Integra, both assembled and bare… (The Sports are the longer shocks, while the Races are the shorter ones)