Bilstein and koni both make kits
It's stuff from their generic race part lines that you can make work
Volvospeed has some solid articles on how to grind off the spring perches and Weld on mounts for std coilover springs
Side note KW are cheap, do NOT source from an aussie reseller (aka import) and they are sub $2k for a full kit
If you simply want lower... do lowering springs
If you want track use only both the front and rear need a lot of re-engineering as per the bttc race bodies and what tvr worked out was actually effective