Stix,

remote glow is basically a lead that hooks up to the glow plug at one end and an outlet that you can plug your glow driver into at the other. It enables you to place the glow driver end in an easier to access place than trying to muck around under the nose of the aircarft. It will only assist with the starting. Once you disconnect the glow driver the engine runs by itself. Onboard glow is a system with a seperate battery onboard which will power the glow plug at whatever settings you set it for.

Its true that with a properly tuned engine you can run an inverted engine without one... however if you are no expert at tuning engines, and I certainly fit into that category, they provide peace of mind knowing that if the engine's getting fuel it will keep running. I had plenty of deadsticks with my tucano until I fitted an onboard glow. None since then! For $60 it's cheap insurance and doesn't add enough weight to affect the performance at all.