Sicce Customer Service is really good. I got a 5.0 as a return pump for my tank and while installing the plumbing we cracked the thread part. 200 bucks down the drain I though but I sent a picture to Sicce and mentioned that I wish the pump was a little sturdier because I just destroyed one and haven't even gotten to use it once.
The shipped me the back assembly (includes the motor) so I could piece together (with the good parts I had left from my first Sicce) a new 5.0 so I wans't out any money even though it could have easily been claimed as user error rather than warranty.