Ah nice to see you've got a lot of it covered already - I don't tend to read the Fb group so hadn't spotted it
suspension wise, anything designed for the KV6 will be a direct bolt on. Pending what you are really after, will depend on that actually is.
I've a set of coilovers on mine, but the srings are firmer than standard, and I'll be honest, the ride is not supple on single rate springs... something possible for the future is progressive springs to ease it back a notch, but probably not likely to bother as I'm getting a more comfortable cruiser soon.
I've also got the Quaife in mine, it is expensive, and I've not yet taken it on the track, but it was bought with that eventual purpose in mind. even on the road it has cut back understeer unless I am really being a fool. It has helped with the torque steer a bit as well.