It's a extremely difficult process of removing the old drive and plugging in the gotek :-)
No modification needed. :-) It just works.
I did found some bugs in the gotek firmware.
I was formatting 10 disks and after disk 3 they al came out as Ndos and the gotek crashed. After reformatting the disk still ndos? Formatting the disk and putting a trash can on it solved it. weird but true.