Digital brewery controller: What buck/boost configuration to get to 240VAC from 208VAC?
With the Direct Fire Gas Control Panel that you have, the Specifications on the web site state 30a, 240v electric, single phase (for safety, please use GFCI protection) so you need to make sure that that GFCI is added to your list. With that said I would ask for a brake down of what that $8,900 is for, it sound a little high to me. All of that work could be done in one day with 2 people.  Also ask the landlord if you could get your own estimate, if he refuses then ask why. Most landlord will let you do what you want (with in the law) as long as you put it back the why you found it when you leave. If you do go with the landlords quote make sure that you get to keep everything that you are paying for.