My advise may sound weird .. but i'd put Tein Zs or As now, and some better coilovers in that 2-3years future of more track-dedicated configuration. Zs are supposedly better then stock, yet very cheap to serve well as interim budget solution. As coilovers also are wear items, why not save more $$$$ for later when you'll go for that future suspension tuning change instead of buying something expensive right away, when you are not yet sure what exactly you want and if what you'll want in future will be same as you are planning for that future now? You can also spend that money on eg. more trackdays improving driver bit.
