Upload & Sell: Off
We don't see a lot of images here with the Sony 10-18, but I don't know why: it's clearly an excellent lens. I'd be surprised if you're going to find a better wide option using the Speedbooster (though it will certainly be nice for narrower fast-aperture stuff).
Oh, I mis-communicated my intent. It would indeed be difficult to find a significantly better UWA to replace the SEL1018, at least at the mid and wide end. Aside from a couple of Contax CZ primes I already have, the Speed Booster was meant to to be used with a 35mm (haven't decided between the Sigma DG HSM, Canon IS USM, or even a used CZ ZE) in lieu of the SEL24F18, and something 85mm-ish. I intend to further explore the limits of low-light social photography. I was just musing that I'd be a little busy for awhile playing with the new toys.