I was going to get the Ikeya formula but got the OEM after some research
Ikeya formula is ideal if you are racing her on track, on a public road , rose joints will take a pounding and you will spend most of your time replacing them, this also brings us onto the ride comfort , she will be noisy crashing over bumps, you wont be taking advantage of the adjustment if she is for the road
The other reservation I have about Ikeya formula is future support, if anything for some reason happens to them , you may be in a spot of bother to get replacement parts
If it is a road car, go OEM, I was in a Supra on track with OEM Suspension and Super pro Polybushed , plus it had the Chris Wilson valved Bilstein's ; she was like a go Kart, I could not believe it , soaked up the bumps ;
Unless she is a track car, save yourself at least 1K and get new OEM
I am sure you seen the video's of Bignum keeping up with exotic machinery around the Nurburgring, he is running OEM