Buying a M235i with a remap

Hi I found a really nice M235i which the previous owner has remapped I wonder if anyone can sort of interpret things so I am more clued up and just give me any info really. I am not very technical to say the least but that's hopefully where you come in.

Receipt says:

EST performance stage 1 custom ECU and TCU software package
Removed and replaced charge pipe from throttle body to intercooler