Decent condition AW11 shells go for about a grand.
Sourcing a 16v 4AG or a rebuilt one is roughly 1000-2000.
I don't know if you've ever worked on any MR-2 but if you don't have a lift, you'll have a fun time raising the rear end as high as possible to get the motor out.
Heres my friends sw20 lol
IF you know what you're doing and your capable of swapping the motor to would be alright for a 3k investment to get the car running but you would probably end up paying at least another 1500 if you were to leave it at a shop for them to do.