This is is the 16600 right? And when you say mod do you mean gen crystal/bezel/insert/crown will fit?
Yes its the 16600 , Mod to do customization, Yes genuine insert, Gen Crown put it on on a WSO tube and save money, Crystal no , if you want gen crystal you need to send it to Adrian ADO213 in England and he can cut the case for a gen spec crystal.
WSO tube
http://www.ebay.com/itm/310801587682?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Gen Spec crystal by WSO
http://www.ebay.com/itm/310802219497?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
or get parts genuine at THE ROLEX FOUN but do not use same screen name and dont mention REPLICA
http://www.rolexforums.com/forumdisplay.php?f=37
Adrians crystal mod
https://forum.replica-watch.info/vb/showthread.php/184087-BP-SD-with-generic-Xtal
Learn here
https://forum.replica-watch.info/vb/showthread.php/141721-BP-Seadweller-Best-SD-available-Period
Reading a lot here is key we wont often answer all your questions