4-1/2"-5" of 3500 psi concrete is all you typically need for a 2 post...wire mesh is good and 4000 psi with wire is better. When we do installations for transit bus hoists, we typically pour 8" slabs (or thicker)...but you sure don't need it for a two post.
We have some good information about two post lifts on our site...
www.standardus.com Look at the articles on the lift pages.
I'll always recommend a US Made product that is ALI / ETL Certified. You will pay more for it, but you be guaranteed that it will have passed some sort of quality control test. Keep in mind that there at least 75 different lift manufacturers out there.....but very few that will be around long enough to get parts and service from 5 years from now. (Many close up and open under a new name when they get sued or go bankrupt!). Stick with an ALI/ETL Certified product, you won't go wrong. (BTW, I've been selling 2 post lifts for over 10 years and never heard of "Team Lifts" prior to this thread.)
Hope all works out for you!