Hi
I have an SC430 which i have owned for 12 years , never had a repair done to it , serviced every year , good quality oil , proper filters , OE cambelts etc , best most reliable older luxury hardtop convertible money can buy . For water in the boot start simple solutions first , high level brake light has two rubber grommets , these perish , i used fish tank sealant , cured first time , the boot filled up before , just remember there are a lot of electrics in the boot , sat nav , amps and roof ecu .
One thing i do need is a front windscreen !!!!!