Dogbox, not Dogbone. Just say'n.
Unless you're an aspiring racecar driver, Dogbox tranny is silly. No syncros is retarded. Daily driving a Dogbox is even more retarded. Every shift you perform with a Dogbox, consists of double clutching and intentional slam shifting.
You can build a strong tranny, without resorting to eliminatiing syncros from the whole assembly. If for any reason you have parts failure in a Dogbox tranny, you will be paying out of your ass for new replacements.
Don't confuse "Dogbox" with spur (straight) cut. Totally different things. One is how gear engagment is initialized, the other is the orientation and axis in which gear teeth are machined. I had straight cut gears (heavy whine) but with double syncros and needle roller conversion. Smooth.
STi trans, I say do it ! Replacements parts are readily available, it's 6 speed, and it's strong.