Sorry to hear your bad experience. I reckon I shouldn't risk it then.
One more query, is it recommended to get a used one or am I asking for trouble again?
I reckon it is all down to the quality of the people working on it. Anything is possible, would think that an electric pump would bring other problems (wiring/fuse/load - And you have to also need to consider the belt routing?). I know that in the past, David Askew has refurbished these pumps before, so that is engineering-wise possible & the most cost-effective remedy. He just didn't have one when mine went bang. Basically you should have a shaft, seal, bearing & impeller so not rocket science, but as I experienced if a thing can go wrong it will. I am no engineer & my experience has been with larger oilfield centrifugal pumps (buying parts not installing them). An e-mail to David won't cost you anything & you can compare it with what your mechanic says, if you trust them. Buying used will postpone the problem by x amount of years but as catman pointed out probably false economy if it would eventually need doing again - good luck.Is it possible to replace the pump with an electric one?