As the title says above, suspension and/or coilover tuning for the touge, which may very well be similar to auto cross. I do apologize for my lack of knowledge on this subject, and I do understand suspension and coilover setups are only the tip of the iceberg. Strut bars, a stickier tyre compound, breaks, and a good balance between horsepower and weight are just to name a few of course. However this is mainly about suspension and coilovers only as I understand a ton of thought goes into this one part, and I don't want to make this to length of a question (However if you do have some other bits of info to offer anything is very much appreciated). Now for the actual question. I recently have gotten into these mountain racing videos, and was curious about the suspension coilover spring setups they may run. I am again, quite a newbie when it comes to this so anything helps, but heres what I know. The pring rates for for the FR-S are. Spoiler: FR-S Spring Rates Various measurements Front OE Spring Rate: Scion FR-S 23 N/mm (131 lbs/in) (2.3kg) (~2300k) Rear OE Spring Rate: Scion FR-S 37 N/mm (211 lbs/in) (3.8kg) (~3800k) Source and credit from BRZ Club and Eibach Springs And the spring rates for the BRZ. Spoiler: BRZ Spring Rates OEM Subaru BRZ Front 0.0"/2.7k OEM Subaru BRZ Rear 0.0"/3.5k From both of these spring rates I have found out that the FR-S tends to be a more tail happy vehicle, and the BRZ more planted. Another strange thing however is that the FR-S tends to have a very slightly faster 0-60 just because of the suspension? Please correct me if I am wrong, but this is what I have heard, and I do know that the BRZ does have an upgraded gearing for better launches which is odd for the FR-S to be slightly faster. Anyways I was curious about suspension tuning in the first place because of the tight mountain road driving (spirited driving with stability in a way), and the fact that I have found myself a set of KW V3's which I do intend on putting on the car with a slight lowering. What concerns me though is the tuning that should be added once they are installed. For example. The KW V's have the ability to. Spoiler: KWs Adjust the rebound, bump, spring rates, and damping, and probably a few other things i may not know about because then again I am a newbie to this. So a another major question I guess, would be the effects of a stiff vs soft suspension. I have heard from many that a stiff suspension is more prone to cause the car to become unstable when hitting the apex due to the shocks not being able to compensate for it thus losing traction and/or control of the vehicle. With soft suspension being prone to more body roll and basically all around bad handling, but probably only comfort. I myself don't understand the rebound, bump, and damping, but maybe you can get what I am trying to ask here. Enough of the talk though. Heres is the type of racing/handling I am talking about. This 86 also got one of the best times on this track which is what really got me going about looking into this. Before you comment I do apologize that this may seem like a messy wall of text, but there is a decent amount of stuff that I do know and I guess a few very similarly related questions.