TEIN Australia are already selling coilover kits and HKS have a plethora of aftermarket goodies ready to go.
Also remember that it is akin to the AE86, a driver's car. The little 4AGE never had a million Sarah Jessica Powers but it screamed like a banshee up in the rev range, was light, nimble and was all about using the chassis. There is no need to put in a 206kw 1JZ into it.