try buy anouther ej20 , was one on eb recently

You'd need another EJ25. They come pretty cheap from places like Ichiban, but as others have pointed out in the past, who knows how long that one would last.
One option would be to pop a second hand EJ25 in and just sell it before it breaks again

first question.
are you competent/ able/ willing to pull out/ replace the motor yourself?
THIS is the deciding factor.
'cause if you are then it's a lot cheaper either way.

Right.
Either way it's going to cost you about $3K to get done and keep the car.

if you just want to cut your losses, you might get 2-3k for it if it has rego and is otherwise in good nick
someone else may be willing to do the engine swap or convert it to turbo.

otherweise you could dump a whole heap of cash into it if you really want te keep the car and drop in a H6 or turbo transplant

$4k is very expensive.
shocks can be rebuilt for about $600 all up, or source some from a GTB legacy from import monster for $500

Am going through a similar issue - big end bearing gone, needs new motor etc etc. Have managed to find one for $1300 and the guys will put it in for $600 (including new fluids, seals etc) so I'll probably go down that route myself... Good luck mate.