Uh, what do you want to do in the garage? Have you got water and drainage in there too?
Check with your a plumber/gasfitter, and see if your residential area can handle a commercial piece of equipment, a lot of places can't. Commercial kitchens are equipped with ventilation, which remove the by-products of gas fired equipment as well as grease laden vapours, and then there is the fire code to be observed. There are those who choose to ignore the fire code, and all is fine until something happens, and then the insurance co. doesn't even want to know your name. If someone is responsible for a fire in a residential area due to flagrant abuse of codes, they won't be very popular with the neighbors...
For electric you don't need venting, just 220 v, and 3 phase if possible, but you can get by with single phase.
