As said previously, you'll need coilovers if you want to go that low. As far as I know the lowest drop you can get with lowering springs is 40mm Regarding rear hubs with discs, your best bet is to check the UKSC for sale section, and look in scrapyards and so on. (you'll also need starlet turbo handbrake cables in order for it to work) For poly bushes and clutch etc, check the traders on UKSC