Tiger or Leopard for Powerbook G4

My trusty recording and secondary laptop is grinding to a halt from years of abuse and the time has come to re-install OS X. It originally ran Panther until I upgraded it to Leopard but it's always been a little slow despite being well within the requirements (it's got a 1.5Ghz G4 and 1GB of RAM). The leopard disks have long gone so I'll have to buy a new disk anyway so would running Tiger instead help speed things up? Will I be able to copy over iLife and CS2 directly or will I need to find some install disks?