There were no glitches during construction. The only really time-consuming part of the project was winding T1, which I did while waiting for the missing caps to show up in the mail. I also put together a serial cable to try out the software that can be downloaded from the Elecraft web site. At first it seemed like the software didn't work. However, testing using HyperTerm on my PC revealed that the serial cable was picking up RF from the K2; winding the cable several times through a large toroid solved the problem, and the software worked great.
By the way, running 10 watts into dipoles and my 80/40 meter end-fed random antenna resulted in 165 contacts in the CQWW contest, including contacts in Australia and Japan on 20 meters (and thanks to both ops for hanging in there with me to get my call sign correctly)! Still can't decide whether I need additional filters; I'll see how the contest goes next February, I guess.