I recently came into ownership of a classic 14 also and wondered about converting it. Granted I'm a newbie so the information below may not be 100% correct. Not sure about the level of effort, seemed about an average job, but the cost was pretty high. Brand new equipment from hobie would cost about $900-1000. Now, if you get used equipment, then that price drops dramatically, but I haven't seen a lot of 14 turbo equip for sale on ebay.

I'm working on converting my 14 piece by piece. The first is the dolphin striker kit (around $80 from Hobie) and trapeze wires ($40). The dolphin striker adds support so that you can hang out. Because the turbo 14 jib blocks are on the tramp vs the front crossbar (16 and above I believe), you have to get some grommets put in (local dealer should be able to help). Then there is the rolling furler, jib, and possibly new lines. I haven't really looked into that yet.

It is possible to do, but if you are looking for the extra jib for power, you might want to consider buying a 16 if you don't want to put in the extra time and money on the 14.

To anyone, if I mispoke about anything, please let me know, cause I'm also interrested in doing this.