Your car really does have a great stance.
I'll be interested to know how it drives as a road car i.e. is it kicking-back or tramlining. I know that trackday tyres alone made my car worse for general use.
Thank you Rob!
I will have to wait to comment until the wheel alignment is correct. I do feel a great potential for a good compromise regarding track and street driving though.
I have limited knowledge compared to many others, but a lot of experience compared to someone who has never been on track. A happy amateur in other words, so take that into consideration. I don't know what your experience is, so you might not agree with me here, but I would love to hear all other ideas around this! There are tons of things to learn!
I usually think a good compromise can be found in having a good sharp car with little or minimal tramlining. I have always been able to achieve this (there are always compromises), and the key I think is getting the toe settings correct along with a good spring/damper combination. The alignment settings you can get away with differs greatly with different tires, like you pointed out. The settings will always need to be adapted for your tire choice to some extent. I prefer the carcass of a track tire, I don't like it when the sidewalls are too soft, I'd rather let the dampers control that (again my preference and it's a compromise). The Yokohama AD08 is so far a good compromise for me, pretty good sidewall, feels like a trackday tire, but maybe not fully as sharp in feel as a R888/A048 or a full blows R-compound tire. It feels better that the Michelin CUP2 in terms of the sidewalls, but not in compound. The CUP2 is my reference as a good daily driver/trackday combination. It's great in that regard.
I am very picky about these things, and a good tire and a good spring/damper combination is where it all starts. And to me this is where people make the biggest mistakes, they buy too cheap dampers, or don't bother choosing a good match. Lowering springs are almost always shit, because the damper will not probably not work to it's best ability with the lower stiffer springs. A car can be stiff but still relatively comfortable, which is where most coilovers shine. I think the BC racing I have on now could be better, but it's a good budget solution. I will need some track time to evaluate better, but a KW V3 looks very very tempting.
My reference regarding a good setup for me is somewhere in between a comfort and race track setting, and this to me is what I refers to as the Nurburgring setup (which is where I've done most of my track driving). I generally prefer a car on the stiffer side, I'd rather sacrifice some comfort for the lack a vagueness (which is what I call it when I loose the feel of the car and it feels indirect and feels floaty). The ring favors softer setup because of all the bumps and elevation changes, which is why stock cars are so fun to drive there. I don't care what the Top Gear hosts say about this, my view is that if a car works well there, it will be an very nice road car as well! A tramlining car will be terrible car there (my 370Z with too wide tires is a great case in point
), so this needs to be solved.
If your car is tramlining, ease off the toe out it the front, or increase! Try it out until it works with your tires. It can be tedious, but check your alignment settings are work off it. Alignment work will cost a little, but to me it's worth it, and it's great value because it can really improve the car. If you need three visits to your shop, so be it!
And regarding a loose rear end, the toe settings in the back is generally a solution there (more so then the LSD settings). Most often you want a little toe in for some stability. I think a adjustable control arm in the rear is a good investment if you have issues there.