NOT A TEACHER
In my opinion, the sentence cannot be paraphrased in that way:
1) We went to Budapest 2 days ago. (It means how many days ago someone was somewhere; a person might have stayed in Budapest more than a month or longer)
2) We had been in Budapest for 2 days, before we got our return tickets. (exactly two days before something happened)
3) We have been in Budapest for 2 days. (It means that someone has been somewhere until now, but we do not know exactly when)
My version is as follows:
We were in Budapest two days ago.
or
We travelled to Budapest two days ago.