10 - 30 minutos
I simply needed just a little more Storage - HDD and RAM - and a little more speed.
Smooth like silk. The replacement took me about 15 Minutes or so - restoring the backup was a little tricky. I have a Macmini with the Timemachine-Function enabled. Started the MBP with DVD and let Timemachine do it's job. Unfortunately it didn't work out 100% like with a restore I remember a couple of years ago. So I opened the MBP again, installed the old HDD, booted, connected a firewire-HDD with appropriate capacity, let Timemachine do the full backup, shut it down, replaced the HDD, booted from DVD with the firewire-HDD connected, let Timemachine do it's job, and it did it well this time.
Resumè: This MBP is performing significantly better AGAIN, the HDD is really fast and the MBP is no longer running out of RAM with VM and other applications running concurrently on the platform. Definitely worth the investment - I expect this machine to run for the next four years.
Be careful with Timemachine when implemented as a network-resource instead of as a directly connected resource. I don't know why the additionally installed applications weren't copied to the system. I haven't missed the checkbox - trust me. However, luckily enough I had another external drive I could utilize to do complete, fresh backup from which I was able to do a complete restore.