Now calm down, Uruk, this is a forum for debate, not simple, petty arguments.
Is a Shogunate victory possible in the Boshin War and would it seriously affect Japans modernization?
Yes, it is possible, albeit barely. Without Tokugawa Yoshinobu resigning as Shogun, the Tokugawas could have amassed enough conservative support (which is the only support they could get) to fight off the Imperials. However, a Tokugawa would necessitate some rather insane changes in government, with the emperor most certainly under home arrest and perhaps even deposed!

Note that this would create huge dissent against the Shogunate in Japan, and necessitate a highly authoritarian state. Essentially, the continuing Tokugawa Shogunate would be along the lines of Siam in its absolutist character, attempting to hold on despite forces attacking at all sides. The Meiji would likely be restored eventually; however, this could push modernization back 10-30 years, which would be both impressive and have horrific consequences for Japan. Possibly, even European areas of influence would be established as the Tokugawas lose almost every battle they fight against the Europeans, which would leave a divided Japan and rather hideous difficulties in unification.
In other words, dude, why do you hate Japan so much?