Search you tube to give you an idea of what a knocking bottom end sounds like, There are a few on there.

Diagnosis is, the bottom end is fooked. Now on the search for a decent low milage engine or decent bottom :-(. It's only money but gonna miss driving it or a while.

i had this creaching problem once on a 94 impreza was giving it some heavy boost and after the sound was really loud like binding and squealing, it turned out timming belt was spinning on a seized up idler control gear bearing against the belt, belt melted and jumped 2 teeth on one bank, engine survived!, but after that i had ticking from one bank.

the bottom end has failed, he posted a while back on a local forum.

Yep bottom end is buggered, rattling around like a good'en. Paul popped around and had a good look and he diagnosed the problem pretty quickly. Just need to sort it now.

Ok, so I know my engine is an EJ20, but can you guys help me with more info. My car is an 03 WRX Blob, 2.0litre turbo. So the bottom end is buggered so I'm looking for a replacement that I can set up so I'm running as I was before. I may have something in the pipeline but if that doesn't work out I just want to keep an eye out on the right stuff that I need as there's a lot of different types I.e closed, semi closed and open deck, rear thrust and centre thrust etc. need to get myself educated sharpish

just get an ej20 out of another blob wrx, the sti engine will be stronger but has avcs heads on it which your ecu cannot control.

See that's it tommy, I was happy with it before it went pop, it's done a few miles running 340bhp so I think it was only a matter of time, as are most things really :-/

For what its worth matey, I was able to source a '99 uk EJ205 engine with 70k for £400 from a local breakers, I had the choice of about 4 too though the others had more miles.
A 2004 engine was available but they were looking 1k with not exactly low mileage.

Certainly worth shopping around.