I believe that Jason84NA2T on z31.com strapped the turbo he is using to a Non-turbo engine. He also has his own website that may have more information on that. You can find him on the forums of z31.com:
If you "slap" a turbo onto any engine, I would bet it will detonate. If you Thoughtfully plan youre conversion, use the right parts, and do it RIGHT it will be fine. Im sure Jason did more than just "slap" a turbo onto an N/A block. You need ignition modification, fuel mods, ect... Anyway dont "slap" anything onto an engine unless you want a "slap" in the face when your car blows.
Everyone is wrong...I have a t3 "slapped" on my n/a block and I run 15psi....you cant be a moron though...without an intercooler, with 93 octane, you can run stock boost. I have an mkiv intercooler with 2.5" piping, plus all exhaust intake, not cat, and all the **** and I have had it like this for 2 years running the **** out of it at the track etc..I run mid 13's and its running perfect..so yes you can "slap" a turbo on the side of an n/a block