Polaris PB-4 Booster Pump

Long time reader, first time caller.
I need some advice, and I truly value the opinions of the people here.

HISTORY:
Long story short, my Polaris Booster pump ruptured a flex line (that was not installed correctly) last summer and was out of commission. So far this year I had a trusted local pool company replace the flex lines (installed correctly) and a good deal of the leaky plumbing/valves and the main pump.

Very excited to have my Polaris back in action, I fired it up a few nights ago but after 5 minutes, water started pouring out of the shaft seal on the booster pump.
No big deal, local pool store had the shaft seal in stock.

PROBLEM:
The problem is the impeller is frozen to the shaft. Being 11 years old it was also brittle, and cracked when I tried to remove it.

QUESTION:
I am asking for opinions/advice on whether you think I should replace the impeller or replace the whole pump.
At this point the remains of the impeller are still stuck on the shaft. If you think I should replace the impeller and salvage the pump any idea how to get it off?

Thanks in advance.

If plastic impeller you can heat with heat gun or use a hacksaw blade cut slot down to shaft , some are pressed on some screw threads, and you need to know if clockwise or counter clockwise threads.