I would have what blue Nick said...and basic hand tools...sockets, ratchets, wrenches, screwdrivers, hammers, pliers, etc. available in like roll carts or something, then have a huge box with all the really cool stuff that would be available on an as needed basis. Tire machine and balancer, brake lathe, A/C machine, maybe an alignment rack.
Definitely tire mounting and balancing (for an additional fee). what's an A/C machine?
"SHELLY" GRAND PRIX GT 02. SLP HEADERS & EXHAUST, K&N CAI, BMR REAR SUSPENSION AND STRUT BRACES, 180 T-STAT, AGX STRUTS, EIBACH SPRINGS, OVERKILLPCM, YELLA TERRA 1.7 ROCKERS, GT1 CAM, SEXMAN PORTED & POLISHED HEADS, STAGE 2 PORTED TB