Web,
The popular modification uses a Byron fan. The plans for making the engine pod and modifications are available from Flying Models magazine. You could use any one of several ducted fan engines, but I highly recommend the OS91 DF engine for best reliability.
Do an RCU search on "ducted fan Enforcer", "Byron Enforcer", or "Byro Blaster Enforcer" and you'l find plenty of information on the conversion. Here's the thread on mine
http://www.rcuniverse.com/forum/m_80.../tm.htm#801604
I don't know what your background is, but from the tone of your postings and since you say you've never built a kit before, you're probably not up to the project. Building this kit per the instructions is pretty straightforward. Once you start modifying things and making parts from plans you'll need the help of an experienced builder, and preferably one with some ducted fan experience.
I suggest that you build a stock Enforcer from your kit. If that goes well and you can get the right kind of help you could modify it or build another DF one later.
Joe