problem for you is mazda changed the whole front end, including all the under-structure, in 99. that's why that dude was able to perform the conversion. he already had a 3rd gen protege, and the 01+ was only considered a "face lift".
or buy that 98 or 99-00 and do wat i did lol but if you believe u can do it go head man. i didnt let that stop me from puting on my 01-03 front end on my 99 protege
323 BA to 323 BJ facelift will be all custom.
Even your fenders won't line up as in lines. Not to mention of the corners around the front windshield and
doors.
Even coming from a 1998 BJ to a 2003 BJ is costly. I only did it because I could and it was worth the adventure.
Looking at the prices for a 2003 BJ for sale in Germany or Romania, you'd be better off buying one.
It will be far cheaper than doing the conversion.
or buy that 98 or 99-00 and do wat i did lol but if you believe u can do it go head man. i didnt let that stop me from puting on my 01-03 front end on my 99 protege