Showcase the tuning, but offer general maintenance(oil/filter, brakes/rotors/lines, coolant, plugs, air filter, exhaust) and tires. How many time have you had a bike on the dyno that really needed tires or asked when they last changed the plugs? If I can ride my bike there get new tires mounted with out the hassle of removing them it would be a plus. Maybe have a few bike stands so the customer can remove the wheels to offset some labor cost.