The biggest concern, is that the person doing the work, not only be proficient, but have the correct toolage to do the work. Like this NCY case boring tool, for installing the larger jugs on the 150 cases, and the knowledge to re-route oil passages, if a "break through occurs.
NCY 150 "kit" with a few extras...
But when it came to doing the 50cc cases, most everyone was hogging them out with dremel tools, not even dissassembling the engine. Later, blaming the crank bearing failures on the BBK, instead of their own inapptitude, and the foreign matter left in the cases to destry the lower end.
Since I had a 150 tool, I scaled it down about 7/8ths, and made a fixture and flycutter to do 50cc cases too.....
NCY150 on the right, homemade 50, on the left...
All's I'm saying, is be sure you hire a professional, that has the tools, and know-how.