I bought a Putnam Monster Stock through Stormer Hobbies and was deeply disappointed. The motor glitched really badly. Lots of people told me it was a capacitor problem so I tried to contact Putnam on 8 different occasions (via email and phone). I never got a return call or email. Oh well, I guess I just won't buy any of their stuff and I won't have to worry about not getting service. I have contacted Axiom, Team Paradigm and Fantom in the past for questions and information and they've always responded in a timely fashion. Pick your motor tuner wisely.
In general, if you do a little reading you can tune off the shelf motors with positive results. One of the only things a motor tuning company can do that most others cannot is balance an armature. Other than that, most tuning tips and tricks are out there for you read and try.