Ahh, I see. I've looked myself, but know Ricmotech doesn't have anything like that. The one I referenced is the only thing I've ever come across. If you ever receive it and install it, I'd love to know your impressions. How long have you been waiting?
Finally going to reply to update. Sorry ahead of time for the continued non-Ricmotech discussion.
I actually ended up ordering two of these. The first I ordered through 3DRap's eBay listing on Dec 19, 2019 and have still not received. Based on tracking it's made it's way to NY finally, but unsure when it will be at my door. The second I ordered directly through their site on Jan 16, 2020 and used the UPS shipping option. That one arrived a few days ago.
Unfortunately after going through the installation I was less than impressed. The mod itself fits into the spring just fine. There's a lip on the bottom of it that is intended to seat directly to the bottom of the spring, and it also is hollow to allow it to fit on top of the spring seat on the pedal housing itself. The hollow of the mod is not large enough for it to fit fully over the spring seat though, so it's is not stable. If you install this and then apply normal brake pressure the spring will bow out and slip because the mod lip that it rests on is not stiff enough to provide a stable foundation. In an effort to make it more stable I actually flipped the spring and installed it with the mod facing up. In that configuration it has plenty of stability, and the lack of stiffness of the mod lip allows it to seat against the pedal itself better.
Regardless of the orientation though the pedal feel was...off. It's doesn't feel like a progressive spring or a load cell. It honestly just feels like a spring with something jammed into it that reduces its "springyness". Pretty bummed that after all this wait it was a total disappointment.
please just stock a progressive brake spring to go with your throttle+clutch combo