Great comments. Keep them coming. I guess I missed on the dead Boxster by about an hour. It just sold while I was waiting for a return phone call.
I do not see the Audi as a hack. It is still Bosch Motronic based. I will probably have to run a new engine harness or at least a few extra wires for the two new cylinders but everthing else should interface quite easily. The reason I like it is that the 4.2 engine fully dressed with electronics can be found for about $1500 with reasonable mileage. 340HP with low end torque should motivate a Boxster with authority.
Yes, the 996 swap is the easiest. I have read all the articles. Figured I could do it in about 2 weekends.
btw, you forgot the 914 in your list.
I have a 300HP WRX powered 914. I figure if I can sort out JDM wiring with non-english manuals then the Audi swap will be no problem. btw, Its fast and raw but not a convertible my wife would drive and it has no AC for the TX summers.
I am still amazed at how expensive 996 motors are. I guess its just demand. I could buy an entire wrecked car for the price of a motor. And yes, I could build a 3.4 powered Boxster for less than a 996.