I owned a Mito and a RS125 in the past and i have to say its nothing short of lunacy going back to one from an SV. Minimatt is spot on with all the maintenance/reliability issues....just a complete pain in the ass....i cant see how an SV, restricted or not, could be worse.
Persevere with the SV IMO. You still get into trouble/kill yourself on a 125....if anything you might consider them more dangerous as they lack oomph unless you are right on the powerband. Dont get me wrong they were fun enough in my youth....but i would never buy another!
Your sig made me LMAO....