All the Venom mods need a soldering iron to do the job.
First try your local DIY forums to see if anyone near you can do the soldering for you. The V-3 and V-4 mods are dead easy to solder in, as long as you have some basic soldering skills.

I got a wide selection of headphones, and use most of them. The K701 is not my headphone of choice though. My D7000 is.

The K701 works fine with the standard BM. The mods are just additional fun bits to add so that you can get a little bit more performance from the standard DAC.